View source for Wiki

{{Short description|Type of website that visitors can edit}}
{{Pp-semi-indef}}
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[[File:Wikitext-wiki markup-wikipedia.png|upright=1.5|thumb|Editing display showing [[MediaWiki markup language|MediaWiki markup language]]|alt=refer to caption]]

A '''wiki''' ({{IPAc-en|audio=en-us-wiki.ogg|ˈ|w|ɪ|k|i}} {{respell|WI|kee}}) is a form of online [[Hypertext|hypertext]] publication that is [[Collaborative editing|collaboratively edited]] and managed by its own audience directly through a [[Software:Web browser|web browser]]. A typical wiki contains multiple pages for the subjects or scope of the project, and could be either open to the public or limited to use within an organization for maintaining its internal [[Knowledge base|knowledge base]].

Wikis are enabled by [[Wiki software|wiki software]], otherwise known as wiki engines. A wiki engine, being a form of a [[Content management system|content management system]], differs from other [[Web application|web-based]] systems such as blog software or [[Static site generator|static site generator]]s, in that the content is created without any defined owner or leader, and wikis have little inherent structure, allowing structure to emerge according to the needs of the users.<ref name="Easy Wiki Hosting "/> Wiki engines usually allow content to be written using a simplified [[Markup language|markup language]] and sometimes edited with the help of a [[Software:Online rich-text editor|rich-text editor]].<ref name="Britannica">{{citation|title=wiki|encyclopedia=[[Encyclopædia Britannica]]|volume=1|publisher=Encyclopædia Britannica, Inc.|year=2007|location=London|url=https://www.britannica.com/EBchecked/topic/1192819/wiki|access-date=April 10, 2008|url-status=live|archive-url=https://web.archive.org/web/20080424074513/https://www.britannica.com/EBchecked/topic/1192819/wiki|archive-date=April 24, 2008}}</ref> There are dozens of different wiki engines in use, both standalone and part of other software, such as [[Software:Bug tracking system|bug tracking system]]s. Some wiki engines are [[Free and open-source software|free and open-source]], whereas others are [[Proprietary software|proprietary]]. Some permit control over different functions (levels of access); for example, editing rights may permit changing, adding, or removing material. Others may permit access without enforcing access control. Further rules may be imposed to organize content.

There are hundreds of thousands of wikis in use, both public and private, including wikis functioning as [[Knowledge management|knowledge management]] resources, note-taking tools, [[Social:Web community|community websites]], and [[Intranet|intranet]]s. [[Biography:Ward Cunningham|Ward Cunningham]], the developer of the first wiki software, [[Social:WikiWikiWeb|WikiWikiWeb]], originally described wiki as "the simplest online database that could possibly work".<ref>{{cite web |last=Cunningham |first=Ward |date=June 27, 2002 |title=What is a Wiki |url=https://www.wiki.org/wiki.cgi?WhatIsWiki |url-status=live |archive-url=https://web.archive.org/web/20080416212802/https://www.wiki.org/wiki.cgi?WhatIsWiki |archive-date=April 16, 2008 |access-date=April 10, 2008 |publisher=WikiWikiWeb}}</ref> "Wiki" (pronounced {{IPA-haw|wiki|}}{{refn|group=note|The realization of the Hawaiian {{IPA|/w/|lang=haw}} [[Social:Phoneme|phoneme]] varies between {{IPA|[w]|lang=haw}} and {{IPA|[v]|lang=haw}}, and the realization of the {{IPA|/k/|lang=haw}} phoneme varies between {{IPA|[k]|lang=haw}} and {{IPA|[t]|lang=haw}}, among other realizations. Thus, the pronunciation of the Hawaiian word ''wiki'' varies between {{IPA|['wiki]|lang=haw}}, {{IPA|['witi]|lang=haw}}, {{IPA|['viki]|lang=haw}}, and {{IPA|['viti]|lang=haw}}. See Hawaiian phonology for more details.}}) is a [[Social:Hawaiian language|Hawaiian]] word meaning "quick".<ref>{{cite web |title=Hawaiian Words; Hawaiian to English |url=https://www.mauimapp.com/moolelo/hwnwdshw.htm |url-status=live |archive-url=https://web.archive.org/web/20080914154748/https://www.mauimapp.com/moolelo/hwnwdshw.htm |archive-date=September 14, 2008 |access-date=September 19, 2008 |publisher=mauimapp.com}}</ref><ref>{{Citation |last=Hasan |first=Heather |title=Wikipedia, 3.5 million articles and counting |url=https://archive.org/details/wikipedia35milli0000hasa/page/11 |page=[https://archive.org/details/wikipedia35milli0000hasa/page/11 11] |year=2012 |archive-url=https://web.archive.org/web/20191026122531/https://archive.org/details/wikipedia35milli0000hasa/page/11 |publisher=New York : Rosen Central |isbn=9781448855575 |access-date=August 6, 2019 |archive-date=October 26, 2019 |url-status=live}}</ref><ref>{{Citation |last=Andrews |first=Lorrin |title=A dictionary of the Hawaiian language to which is appended an English-Hawaiian vocabulary and a chronological table of remarkable events |url=https://archive.org/details/dictionaryofhawa00andrrich/ |page=514 |year=1865 |archive-url=https://web.archive.org/web/20140815064248/https://archive.org/details/dictionaryofhawa00andrrich/ |publisher=Henry M. Whitney |access-date=June 1, 2014 |archive-date=August 15, 2014 |url-status=live}}</ref>

The online encyclopedia project [[Wikipedia]] is the most popular wiki-based website, and is one of the most widely viewed sites in the world, having been ranked in the top twenty since 2007.<ref name="Alexa Top Sites">{{cite web|url=https://www.alexa.com/topsites|title=Alexa Top Sites|access-date=December 1, 2016|url-status=live|archive-url=https://web.archive.org/web/20150302173920/https://www.alexa.com/topsites|archive-date=March 2, 2015}}</ref> Wikipedia is not a single wiki but rather a collection of hundreds of wikis, with each one pertaining to a specific language. The English-language Wikipedia has the largest collection of articles: {{As of|2024|January|lc=y|post=,}} it has over six million articles.<ref>{{cite web|title=Wikipedia:Size of Wikipedia|url=https://en.wikipedia.org/wiki/Wikipedia:Size_of_Wikipedia |access-date=January 14, 2024|publisher=[[Organization:Wikimedia Foundation|Wikimedia Foundation]]|website=[[Wikipedia]]}}</ref>

==Characteristics==
[[File:Ward Cunningham - Commons-1.jpg|thumb|upright=0.9|Ward Cunningham]]

In their 2001 book ''The Wiki Way: Quick Collaboration on the Web'', [[Biography:Ward Cunningham|Ward Cunningham]] and co-author Bo Leuf described the essence of the Wiki concept:<ref>{{cite book |title= The Wiki Way: Quick Collaboration on the Web |last2= Leuf |first2= Bo |last1= Cunningham |first1= Ward |oclc= 45715320 |publisher= Addison–Wesley |date= April 13, 2001 |isbn= 9780201714999 |url= https://archive.org/details/isbn_9780201714999 }} [https://books.google.com/books?id=JmvbAAAAMAAJ Google Books page] {{Webarchive|url=https://web.archive.org/web/20230111053231/https://www.google.co.in/books/edition/_/JmvbAAAAMAAJ |date=January 11, 2023 }}</ref><ref>{{cite web |url=https://c2.com/cgi/wiki?WikiDesignPrinciples |title= Wiki Design Principles |access-date=2002-04-30 |url-status=dead |archive-url=https://web.archive.org/web/20020430181259/https://c2.com/cgi/wiki?WikiDesignPrinciples |archive-date=April 30, 2002}}</ref>{{pn|date=October 2022}}
* "A wiki invites all users—not just experts—to edit any [[Web page|page]] or to create new pages within the wiki web site, using only a standard [[Vanilla software|'plain-vanilla']] Web browser without any extra [[Software:Browser extension|add-ons]]."
* "Wiki promotes meaningful topic associations between different pages by making page link creation intuitively easy and showing whether an intended target page exists or not."
* "A wiki is ''not'' a carefully crafted site created by experts and professional writers and designed for casual visitors. Instead, it seeks to involve the typical visitor/user in an ongoing process of creation and collaboration that constantly changes the website landscape."

A wiki enables [[Social:Community|communities]] of editors and contributors to write documents collaboratively. All that people require to contribute is a computer, [[Internet]] access, a [[Software:Web browser|web browser]], and a basic understanding of a simple markup language (e.g. [[MediaWiki markup language]]). A single page in a wiki website is referred to as a "wiki page", while the entire collection of pages, which are usually well-interconnected by [[Hyperlink|hyperlink]]s, is "the wiki". A wiki is essentially a [[Database|database]] for creating, browsing, and searching through information. A wiki allows [[Nonlinear system|non-linear]], evolving, complex, and networked text, while also allowing for editor argument, debate, and interaction regarding the content and [[Formatted text|formatting]].<ref name="Legal">{{citation|title=Legal Issues for Wikis: The Challenge of User-generated and Peer-produced Knowledge, Content and Culture|last1=Black|first1=Peter|last2=Delaney|first2=Hayden|last3=Fitzgerald|first3=Brian|volume=14|publisher=eLaw J.|year=2007|url=https://elaw.murdoch.edu.au/archives/issues/2007/1/eLaw_legal%20issues%20for%20wikis.pdf|url-status=dead|archive-url=https://web.archive.org/web/20121222125337/https://elaw.murdoch.edu.au/archives/issues/2007/1/eLaw_legal%20issues%20for%20wikis.pdf|archive-date=December 22, 2012}}</ref> A defining characteristic of wiki technology is the ease with which pages can be created and updated. Generally, there is no review by a moderator or [[Social:Gatekeeping (communication)|gatekeeper]] before modifications are accepted and thus lead to changes on the website. Many wikis are open to alteration by the general public without requiring registration of [[User (computing)|user]] accounts. Many edits can be made in real-time and appear almost instantly online, but this feature facilitates abuse of the system. Private wiki servers require [[Authentication|user authentication]] to edit pages, and sometimes even to read them. Maged N. Kamel Boulos, Cito Maramba, and Steve Wheeler write that the open wikis produce a process of [[Social:Social Darwinism|Social Darwinism]]. "... because of the openness and rapidity that wiki pages can be edited, the pages undergo an evolutionary selection process, not unlike that which nature subjects to living organisms. 'Unfit' sentences and sections are ruthlessly culled, edited and replaced if they are not considered 'fit', which hopefully results in the evolution of a higher quality and more relevant page."<ref name=BMC/>
=== Editing ===
==== Source editing ====
Some wikis have an edit button or link directly on the page being viewed if the user has permission to edit the page. This can lead to a text-based editing page where participants can structure and format wiki pages with a simplified markup language, sometimes known as wikitext, wiki markup or wikicode (it can also lead to a [[WYSIWYG]] editing page; see the paragraph after the table below). For example, starting lines of text with asterisks could create a bulleted list. The style and syntax of wikitexts can vary greatly among [[Software:List of wiki software|wiki implementations]],{{example needed|date=August 2018}} some of which also allow HTML tags.

==== Layout consistency ====
Wikis have favored plain-text editing, with fewer and simpler conventions than HTML for indicating style and structure. Although limiting access to HTML and [[Cascading Style Sheets]] (CSS) of wikis limits user ability to alter the structure and formatting of wiki content, there are some benefits. Limited access to CSS promotes consistency in the look and feel, and having [[JavaScript]] disabled prevents a user from implementing code that may limit other users' access.

==== Basic syntax ====
{| class="wikitable noprint"
|-
! style="width:33.3%;"|[[Software:MediaWiki|MediaWiki]] [[Syntax (programming languages)|syntax]]<br><span style="font-weight: normal; font-size: 98%">(the [[Source code|source code]] used to add formatting to text)</span>

! style="width:33.3%;"|HTML equivalent<br><span style="font-weight: normal; font-size: 98%">(web code used to add formatting to text)</span>

! style="width:33.3%;"|Rendered output<br><span style="font-weight: normal; font-size: 98%">(as seen by visitors of the wiki)</span>
|- style="vertical-align:top;"
|<source lang="wikitext">"Take some more tea," the March Hare said to Alice, very earnestly.

"I've had '''nothing''' yet," Alice replied in an offended tone, "so I can't take more."

"You mean you can't take ''less''," said the Hatter. "It's very easy to take ''more'' than nothing."</source>
|<source lang="html"><p>"Take some more <a href="/wiki/Tea" title="Tea">tea</a>," the March Hare said to Alice, very earnestly.</p>

<p>"I've had <b>nothing</b> yet," Alice replied in an offended tone, "so I can't take more."</p>

<p>"You mean you can't take <i>less</i>," said the Hatter. "It's very easy to take <i>more</i> than nothing."</p></source>
|<br>"Take some more tea," the March Hare said to Alice, very earnestly.

"I've had '''nothing''' yet," Alice replied in an offended tone, "so I can't take more."

"You mean you can't take ''less''," said the Hatter. "It's very easy to take ''more'' than nothing."
|}
{{anchor|visual}} {{anchor|wysiwyg}} {{anchor|WYSIWYG}}

==== Visual editing ====
Wikis can also make [[WYSIWYG]] editing available to users, usually through a [[JavaScript]] control that translates graphically entered formatting instructions into the corresponding [[HTML element|HTML tags]] or wikitext. In those implementations, the markup of a newly edited, marked-up version of the page is generated and submitted to the server [[Transparency (human–computer interaction)|transparently]], shielding the user from this technical detail. An example of this is the [[Software:VisualEditor|VisualEditor]] on Wikipedia. WYSIWYG controls do not, however, always provide all the features available in wikitext, and some users prefer not to use a WYSIWYG editor. Hence, many of these sites offer some means to edit the wikitext directly.

==== Version history ====
Some wikis keep a record of changes made to wiki pages; often, every version of the page is stored. This means that authors can revert to an older version of the page should it be necessary because a mistake has been made, such as the content accidentally being deleted or the page has been vandalized to include offensive or malicious text or other inappropriate content.

==== Edit summary ====
{{Self reference|"Edit summary" redirects here. For the Wikipedia help page, see Help:Edit summary.}}

Many wiki implementations, such as [[Software:MediaWiki|MediaWiki]], the [[Software|software]] that powers [[Wikipedia]], allow users to supply an ''edit summary'' when they edit a page. This is a short piece of text summarizing the changes they have made (e.g. "Corrected grammar" or "Fixed formatting in table"). It is not inserted into the article's main text but is stored along with that revision of the page, allowing users to explain what has been done and why. This is similar to a log message when making changes in a revision-control system. This enables other users to see which changes have been made by whom and why, often in a list of summaries, dates and other short, relevant content, a list which is called a "log" or "history".

===Navigation===
Within the text of most pages, there are usually many [[Hypertext|hypertext]] links to other [[Web page|pages]] within the wiki. This form of non-linear navigation is more "native" to a wiki than structured/formalized navigation schemes. Users can also create any number of index or table-of-contents pages, with hierarchical categorization or whatever form of organization they like. These may be challenging to maintain "by hand", as multiple authors and users may create and delete pages in an ad hoc, unorganized manner. Wikis can provide one or more ways to categorize or tag pages to support the maintenance of such index pages. Some wikis, including the original, have a [[Backlink|backlink]] feature, which displays all pages that link to a given page. It is also typically possible in a wiki to create links to pages that do not yet exist, as a way to invite others to share what they know about a subject new to the wiki. Wiki users can typically "tag" pages with categories or keywords, to make it easier for other users to find the article. For example, a user creating a new article on [[Engineering:Cold-weather biking|cold-weather biking]] might "tag" this page under the categories of commuting, winter sports and bicycling. This would make it easier for other users to find the article.

===Linking and creating pages===
[[Link aggregation|Links]] are created using a specific syntax, the so-called "link pattern". Originally, most wikis{{citation needed|date=July 2013}} used CamelCase to name pages and create links. These are produced by capitalizing words in a phrase and removing the spaces between them (the word "CamelCase" is itself an example). While CamelCase makes linking easy, it also leads to links in a form that deviates from the standard spelling. To link to a page with a single-word title, one must abnormally capitalize one of the letters in the word (e.g. "WiKi" instead of "Wiki"). CamelCase-based wikis are instantly recognizable because they have many links with names such as "TableOfContents" and "BeginnerQuestions". A wiki can render the visible anchor of such links "pretty" by reinserting spaces, and possibly also reverting to lower case. This reprocessing of the link to improve the readability of the anchor is, however, limited by the loss of capitalization information caused by CamelCase reversal. For example, "RichardWagner" should be rendered as "Richard Wagner", whereas "PopularMusic" should be rendered as "popular music". There is no easy way to determine which capital letters should remain capitalized. As a result, many wikis now have "free linking" using brackets, and some disable CamelCase by default.

===Searching===
Most wikis offer at least a title [[Search algorithm|search]], and sometimes a full-text search. The scalability of the search depends on whether the wiki engine uses a database. Some wikis, such as [[Software:PmWiki|PmWiki]], use flat files.<ref name=Augar>{{cite journal |title=Teaching and learning online with wikis |pages=95–104 |last1=Naomi |first1=Augar |first2=Ruth |last2=Raitman |first3=Wanlei |last3=Zhou |journal =Proceedings of Beyond the Comfort Zone: 21st ASCILITE Conference |citeseerx=10.1.1.133.1456|year=2004}}</ref> MediaWiki's first versions used flat files, but it was rewritten by Lee Daniel Crocker in the early 2000s (decade) to be a database application.{{cn|date=April 2020}} Indexed database access is necessary for high speed searches on large wikis. Alternatively, external [[Web search engine|search engines]] such as [[Software:Google Search|Google Search]] can sometimes be used on wikis with limited searching functions to obtain more precise results.

==History==
[[File:Wikiwiki2008.JPG|thumb|Wiki Wiki Shuttle at Honolulu International Airport]]
[[Social:WikiWikiWeb|WikiWikiWeb]] was the first wiki.<ref name="ebersbach10">{{harvnb|Ebersbach|2008|p=10}}</ref> Ward Cunningham started developing WikiWikiWeb in {{wipe|Portland, Oregon}}, Oregon, in 1994, and installed it on the [[Domain name|Internet domain]] c2.com on March 25, 1995. It was named by Cunningham, who remembered a Honolulu International Airport counter employee telling him to take the "Wiki Wiki Shuttle" bus that runs between the airport's terminals. According to Cunningham, "I chose wiki-wiki as an alliterative substitute for 'quick' and thereby avoided naming this stuff quick-web."<ref name="cunningham">{{cite web | last = Cunningham | first = Ward | url = https://c2.com/doc/etymology.html | title = Correspondence on the Etymology of Wiki | date = November 1, 2003 | publisher = WikiWikiWeb | access-date = March 9, 2007 | url-status=live | archive-url = https://web.archive.org/web/20070317120823/https://c2.com/doc/etymology.html | archive-date = March 17, 2007 | df = mdy-all }}</ref><ref name="history">{{cite web |last=Cunningham |first=Ward |url=https://c2.com/cgi/wiki?WikiHistory |title=Wiki History |publisher=WikiWikiWeb |date=February 25, 2008 |access-date=March 9, 2007 |url-status=live |archive-url=https://web.archive.org/web/20020621221535/https://c2.com/cgi/wiki?WikiHistory |archive-date=June 21, 2002  }}</ref>

Cunningham was, in part, inspired by the Apple [[Software:HyperCard|HyperCard]], which he had used. HyperCard, however, was single-user.<ref name="artima">{{cite web |title=Exploring with Wiki: A Conversation with Ward Cunningham, Part I |author=Bill Venners |date=October 20, 2003 |url=https://www.artima.com/intv/wiki.html |publisher=artima developer |access-date=December 12, 2014 |url-status=live |archive-url=https://web.archive.org/web/20150205091836/https://www.artima.com/intv/wiki.html |archive-date=February 5, 2015  }}</ref> [[Company:Apple Inc.|Apple]] had designed a system allowing users to create virtual "card stacks" supporting links among the various cards. Cunningham developed [[Biography:Vannevar Bush|Vannevar Bush]]'s ideas by allowing users to "comment on and change one another's text."<ref name="Britannica"/><ref name="hypercard">{{cite web | last = Cunningham | first = Ward | url = https://c2.com/cgi/wiki?WikiWikiHyperCard | title = Wiki Wiki Hyper Card | publisher = WikiWikiWeb | date = July 26, 2007 | access-date = March 9, 2007 | url-status=live | archive-url = https://web.archive.org/web/20070406064446/https://c2.com/cgi/wiki?WikiWikiHyperCard | archive-date = April 6, 2007 | df = mdy-all }}</ref> Cunningham says his goals were to link together people's experiences to create a new literature to document programming [[Pattern language|patterns]], and to harness people's natural desire to talk and tell stories with a technology that would feel comfortable to those not used to "authoring".<ref name="artima" />

Wikipedia became the most famous wiki site, launched in January 2001 and entering the top ten most popular websites in 2007. In the early 2000s (decade), wikis were increasingly adopted in enterprise as collaborative software. Common uses included project communication, [[Intranet|intranets]], and documentation, initially for technical users. Some companies use wikis as their only collaborative software and as a replacement for static intranets, and some schools and universities use wikis to enhance group learning. There may be greater use of wikis behind [[Firewall (computing)|firewalls]] than on the public Internet. On March 15, 2007, the word ''wiki'' was listed in the online ''Oxford English Dictionary''.<ref name="OED1">{{cite dictionary | url = https://www.oed.com/public/update0703/march-2007-update | title = March 2007 update | dictionary = Oxford English Dictionary | date = March 1, 2007 | last = Diamond | first = Graeme | access-date = March 16, 2007 | url-status=live | archive-url = https://web.archive.org/web/20110107132110/https://www.oed.com/public/update0703/march-2007-update | archive-date = January 7, 2011 | df = mdy-all }}</ref>

==Alternative definitions==
In the late 1990s and early 2000s, the word "wiki" was used to refer to both user-editable websites and the software that powers them; the latter definition is still occasionally in use.<ref name="Easy Wiki Hosting">{{citation |url=https://msdn.microsoft.com/en-us/magazine/cc700339.aspx |title=Easy Wiki Hosting, Scott Hanselman's blog, and Snagging Screens |date=July 2008 |last=Mitchell |first=Scott |publisher=MSDN Magazine |access-date=March 9, 2010 |url-status=live |archive-url=https://web.archive.org/web/20100316192702/https://msdn.microsoft.com/en-us/magazine/cc700339.aspx |archive-date=March 16, 2010  }}</ref> Wiki inventor Ward Cunningham wrote in 2014<ref>{{Cite tweet|number=531149812976996352|user=WardCunningham|title=The plural of wiki is wiki. See https://forage.ward.fed.wiki.org/an-install-of-wiki.html|author=Ward Cunningham|date=November 8, 2014|access-date=March 18, 2019}}</ref> that the word "wiki" should not be used to refer to a single website, but rather to a mass of user-editable pages or sites so that a single website is not "a wiki" but "an instance of wiki". He wrote that the concept of wiki federation, in which the same content can be hosted and edited in more than one location in a manner similar to [[Distributed version control|distributed version control]], meant that the concept of a single discrete "wiki" no longer made sense.<ref>{{cite web|url=https://forage.ward.fed.wiki.org/view/an-install-of-wiki|title=Smallest Federated Wiki|work=wiki.org|access-date=September 28, 2015|url-status=live|archive-url=https://web.archive.org/web/20150928165957/https://forage.ward.fed.wiki.org/view/an-install-of-wiki|archive-date=September 28, 2015}}</ref>

==Implementations==
[[Wiki software]] is a type of [[Collaborative software|collaborative software]] that runs a wiki system, allowing web pages to be created and edited using a common web browser. It may be implemented as a series of [[Scripting language|scripts]] behind an existing [[Web server|web server]] or as a standalone [[Application server|application server]] that runs on one or more web servers. The content is stored in a [[File system|file system]], and changes to the content are stored in a [[Relational database|relational database]] management system. A commonly implemented software package is [[Software:MediaWiki|MediaWiki]], which runs Wikipedia. Alternatively, [[Social:Personal wiki|personal wiki]]s run as a standalone application on a single computer.

Wikis can also be created on a "[[Company:Wiki hosting service|wiki farm]]", where the [[Server-side|server-side]] software is implemented by the wiki farm owner. Some wiki farms can also make private, password-protected wikis. Free wiki farms generally contain advertising on every page. For more information, see [[Software:Comparison of wiki hosting services|Comparison of wiki hosting services]].

==Trust and security==

===Controlling changes===
{{Self reference|"Recent changes" redirects here. For the Wikipedia help page, see Help:Recent changes. For the recent changes page itself, see Special:RecentChanges.}}
[[File:History Comparison Example (Vector).png|thumb|History comparison reports highlight the changes between two revisions of a page.]]
Wikis are generally designed with the philosophy of making it easy to correct mistakes, rather than making it difficult to make them. Thus, while wikis are very open, they provide a means to verify the validity of recent additions to the body of pages. The most prominent, on almost every wiki, is the "Recent Changes" page—a specific list showing recent edits, or a list of edits made within a given time frame.<ref>{{harvnb|Ebersbach|2008|p=20}}</ref> Some wikis can filter the list to remove minor edits and edits made by automatic importing scripts ("bots").<ref>{{harvnb|Ebersbach|2008|p=54}}</ref> From the change [[Logging (computing)|log]], other functions are accessible in most wikis: the [[Changelog|revision history]] shows previous page versions and the [[Software:Diff|diff]] feature highlights the changes between two revisions. Using the revision history, an editor can view and restore a previous version of the article. This gives great power to the author to eliminate edits. The diff feature can be used to decide whether or not this is necessary. A regular wiki user can view the diff of an edit listed on the "Recent Changes" page and, if it is an unacceptable edit, consult the history, restoring a previous revision; this process is more or less streamlined, depending on the wiki software used.<ref>{{harvnb|Ebersbach|2008|p=178}}</ref>

In case unacceptable edits are missed on the "recent changes" page, some wiki engines provide additional content control. It can be [[Software:Remote monitoring and management|monitored]] to ensure that a page, or a set of pages, keeps its quality. A person willing to maintain pages will be warned of modifications to the pages, allowing them to verify the validity of new editions quickly. This can be seen as a very pro-author and anti-editor feature.<ref>{{harvnb|Ebersbach|2008|p=109}}</ref> A watchlist is a common [[Implementation|implementation]] of this. Some wikis also implement "patrolled revisions", in which editors with the requisite credentials can mark some edits as not vandalism. A "flagged revisions" system can prevent edits from going live until they have been reviewed.<ref>{{citation|title=Wikipedia's Labor Squeeze and its Consequences|journal=Journal on Telecommunications and High Technology Law|last = Goldman | first = Eric|volume=8}}</ref>

===Trustworthiness and reliability of content===
Critics of publicly editable wiki systems argue that these systems could be easily tampered with by malicious individuals ("vandals") or even by well-meaning but unskilled users who introduce errors into the content, while proponents maintain that the community of users can catch such malicious or erroneous content and correct it.<ref name="Britannica"/> Lars Aronsson, a [[Data system|data systems]] specialist, summarizes the controversy as follows: "Most people when they first learn about the wiki concept, assume that a Web site that can be edited by anybody would soon be rendered useless by destructive input. It sounds like offering free spray cans next to a grey concrete wall. The only likely outcome would be ugly graffiti and simple tagging and many artistic efforts would not be long lived. Still, it seems to work very well."<ref name="ebersbach10"/> High editorial standards in medicine and health sciences articles, in which users typically use peer-reviewed journals or university textbooks as sources, have led to the idea of expert-moderated wikis.<ref>{{Cite journal |last1=Barsky |first1=Eugene |last2=Giustini |first2=Dean |date=December 2007 |title=Introducing Web 2.0: wikis for health librarians |url=https://circle.ubc.ca/bitstream/handle/2429/497/c07-036.pdf |url-status=live |volume=28 |issue=4 |pages=147–150 |doi=10.5596/c07-036 |issn=1708-6892 |archive-url=https://web.archive.org/web/20120430195019/https://circle.ubc.ca/bitstream/handle/2429/497/c07-036.pdf |archive-date=April 30, 2012 |access-date=November 7, 2011 |journal=Journal of the Canadian Health Libraries Association |doi-access=free }}</ref> Some wikis allow one to link to specific versions of articles, which has been useful to the scientific community, in that expert peer reviewers could analyse articles, improve them and provide links to the trusted version of that article.<ref>{{Cite journal |last=Yager |first=Kevin |date=March 16, 2006 |title=Wiki ware could harness the Internet for science |journal=Nature |volume=440 |issue=7082 |pages=278 |bibcode=2006Natur.440..278Y |doi=10.1038/440278a |pmid=16541049 |doi-access=free }}</ref> Noveck points out that "participants are accredited by members of the wiki community, who have a vested interest in preserving the quality of the work product, on the basis of their ongoing participation." On controversial topics that have been subject to disruptive editing, a wiki author may restrict editing to registered users.<ref name=Noveck/>

===Security===
{{Self reference|"Edit war" redirects here. It is not to be confused with [[Edit conflict]]. For Wikipedia's policy on edit warring, see Wikipedia:Edit warring.}}
The open philosophy of wiki&nbsp;– allowing anyone to edit content – does not ensure that every editor's intentions are well-mannered. For example, vandalism (changing wiki content to something offensive, adding nonsense, maliciously removing content, or deliberately adding incorrect information, such as hoax information) can be a major problem. On larger wiki sites, such as those run by the [[Organization:Wikimedia Foundation|Wikimedia Foundation]], vandalism ''can ''go unnoticed for some period of time. Wikis, because of their open nature, are susceptible to intentional disruption, known as "trolling".
Wikis tend to take a ''soft-security'' approach to the problem of vandalism, making damage easy to undo rather than attempting to prevent damage. Larger wikis often employ sophisticated methods, such as bots that automatically identify and revert vandalism and JavaScript enhancements that show characters that have been added in each edit. In this way, vandalism can be limited to just "minor vandalism" or "sneaky vandalism", where the characters added/eliminated are so few that bots do not identify them and users do not pay much attention to them.<ref>{{cite web |url=https://m3m.homelinux.org/wikiMC/index.php/Security |title=Security |publisher=Assothink |access-date=February 16, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20140106040941/https://m3m.homelinux.org/wikiMC/index.php/Security |archive-date=January 6, 2014  }}</ref>{{Unreliable source?|date=July 2013|failed=y}} An example of a bot that reverts vandalism on Wikipedia is ClueBot NG. ClueBot NG, which uses [[Machine learning|machine learning]] to identify likely vandalism, can revert edits, often within minutes, if not seconds.<ref>{{cite web|url = https://www.theverge.com/2014/2/18/5412636/this-machine-kills-trolls-how-wikipedia-robots-snuff-out-vandalism|title = This machine kills trolls|date = February 18, 2014|access-date = September 7, 2014|website = [[The Verge]]|last = Hicks|first = Jesse|url-status=live|archive-url = https://web.archive.org/web/20140827115824/https://www.theverge.com/2014/2/18/5412636/this-machine-kills-trolls-how-wikipedia-robots-snuff-out-vandalism|archive-date = August 27, 2014|df = mdy-all}}</ref>

The amount of vandalism a wiki receives depends on how open the wiki is. For instance, some wikis allow unregistered users, identified by their [[IP address]]es, to edit content, while others limit this function to just registered users.<ref>{{harvnb|Ebersbach|2008|p=108}}</ref> 

Edit wars can also occur as users repetitively revert a page to the version they favor. In some cases, editors with opposing views of which content should appear or what formatting style should be used will change and re-change each other's edits. This results in the page being "unstable" from a general user's perspective, because each time a general user comes to the page, it may look different. Some wiki software allows an administrator to stop such edit wars by locking a page from further editing until a decision has been made on what version of the page would be most appropriate.<ref name=Legal/> Some wikis are in a better position than others to control behavior due to governance structures existing outside the wiki. For instance, a college teacher can create incentives for students to behave themselves on a class wiki they administer by limiting editing to logged-in users and pointing out that all contributions can be traced back to the contributors. Bad behavior can then be dealt with under university policies.<ref name=Augar/> 

====Potential malware vector====
[[Malware]] can also be a problem for wikis, as users can add links to sites hosting malicious code. For example, a German Wikipedia article about the Blaster Worm was edited to include a hyperlink to a malicious website. Users of vulnerable Microsoft Windows systems who followed the link would be infected.<ref name=Legal/> A countermeasure is the use of software that prevents users from saving an edit that contains a link to a site listed on a [[Blacklist (computing)|blacklist]] of malicious sites.

==Communities==

===Applications===
[[File:EnglishWikipedia 29June2017.png|thumb|right|The home page of the English Wikipedia]]
The English Wikipedia has the largest user base among wikis on the [[World Wide Web]]<ref>{{cite web|url=https://s23.org/wikistats/largest_html.php?sort=users_desc&th=8000&lines=500 |title=List of largest (Media)wikis |access-date=December 12, 2014 |publisher=S23-Wiki |date=April 3, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20140825164715/https://s23.org/wikistats/largest_html.php?sort=users_desc&th=8000&lines=500 |archive-date=August 25, 2014 }}</ref> and ranks in the top 10 among all Web sites in terms of traffic.<ref>{{cite web|url=https://www.alexa.com/topsites|title=Alexa Top 500 Global Sites|access-date=April 26, 2015|publisher=[[Company:Alexa Internet|Alexa Internet]]|url-status=live|archive-url=https://web.archive.org/web/20150302173920/https://www.alexa.com/topsites|archive-date=March 2, 2015}}</ref> Other large wikis include the [[Social:WikiWikiWeb|WikiWikiWeb]], [[Memory Alpha]], Wikivoyage, and previously [[Susning.nu]], a Swedish-language knowledge base. [[Medicine:List of medical wikis|Medical]] and health-related wiki examples include [[Ganfyd]], an online collaborative medical reference that is edited by medical professionals and invited non-medical experts.<ref name=BMC>{{citation|title=Wikis, blogs and podcasts: a new generation of Web-based tools for virtual collaborative clinical practice and education |doi=10.1186/1472-6920-6-41|pmc=1564136|journal=BMC Medical Education|volume=6|pmid=16911779|page=41|year=2006|first1=M. N. K.|last1=Boulos|first2=I.|last2=Maramba|first3=S.|last3=Wheeler |doi-access=free }}</ref> Many wiki [[Online community|communities]] are private, particularly within [[Software:Enterprise software|enterprises]]. They are often used as internal documentation for in-house systems and applications. Some companies use wikis to allow customers to help produce software documentation.<ref>{{cite journal | title = Wikis for Collaborative Software Documentation | first1 = C. | last1 = Müller | first2 = L. | last2 = Birn | url = https://i-know.tugraz.at/wp-content/uploads/2008/11/47_wikis-for-collaborative-software-documentation.pdf | publisher = Proceedings of I-KNOW '06 | date = September 6–8, 2006 | url-status=dead | archive-url = https://web.archive.org/web/20110706095145/https://i-know.tugraz.at/wp-content/uploads/2008/11/47_wikis-for-collaborative-software-documentation.pdf |website=i-know.tugraz.at | archive-date = July 6, 2011 | df = mdy-all }}</ref> A study of corporate wiki users found that they could be divided into "synthesizers" and "adders" of content. Synthesizers' frequency of contribution was affected more by their impact on other wiki users, while adders' contribution frequency was affected more by being able to accomplish their immediate work.<ref>{{citation |first1 = A. | last1 = Majchrzak | first2 = C. | last2 = Wagner | first3 = D. | last3 = Yates |chapter=Corporate wiki users: results of a survey |title=Proceedings of the 2006 international symposium on Wikis | publisher=Symposium on Wikis |year=2006 |pages=99–104 |doi=10.1145/1149453.1149472 |isbn=978-1-59593-413-0 | s2cid = 13206858 }}</ref> From a study of thousands of wiki deployments, Jonathan Grudin concluded careful stakeholder analysis and education are crucial to successful wiki deployment.<ref>{{cite journal |url=https://research.microsoft.com/apps/pubs/default.aspx?id=138573 |title=Wikis at work: Success factors and challenges for sustainability of enterprise wikis  |first1=Jonathan |last1=Grudin |first2=Erika Shehan |last2=Poole |website=Microsoft Research |year=2015 |access-date=June 16, 2015 |url-status=live |archive-url=https://web.archive.org/web/20150904031729/https://research.microsoft.com/apps/pubs/default.aspx?id=138573 |archive-date=September 4, 2015  }}</ref>

In 2005, the Gartner Group, noting the increasing popularity of wikis, estimated that they would become mainstream collaboration tools in at least 50% of companies by 2009.<ref>{{citation|first=Michelle|last=Conlin|title=E-Mail Is So Five Minutes Ago|date=November 28, 2005|work=Bloomberg BusinessWeek|url=https://www.businessweek.com/stories/2005-11-27/e-mail-is-so-five-minutes-ago|url-status=dead|archive-url=https://web.archive.org/web/20121017131307/https://www.businessweek.com/stories/2005-11-27/e-mail-is-so-five-minutes-ago|archive-date=October 17, 2012}}</ref>{{update inline|date=July 2013}} Wikis can be used for [[Project management|project management]].<ref>{{cite web|title=HomePage|url=https://projectmanagementwiki.org|work=Project Management Wiki.org|accessdate=May 8, 2012|url-status=live|archiveurl=https://web.archive.org/web/20140816221509/https://projectmanagementwiki.org/|archivedate=August 16, 2014}}</ref><ref>{{cite web|title=Ways to Wiki: Project Management|url=https://www.editme.com/Ways-to-Wiki-Project-Management|work=EditMe|date=January 4, 2010|url-status=live|archiveurl=https://web.archive.org/web/20120508152328/https://www.editme.com/Ways-to-Wiki-Project-Management|archivedate=May 8, 2012}}</ref>{{unreliable source?|failed=y|date=July 2013}} Wikis have also been used in the academic community for sharing and dissemination of information across institutional and international boundaries.<ref>{{cite journal |url=https://portal.acm.org/citation.cfm?id=1142215.1142259|title=SensorWiki.org: a collaborative resource for researchers and interface designers |isbn=978-2-84426-314-8|first1 = M. M. | last1 = Wanderley | first2 = D. | last2 = Birnbaum | first3 = J. | last3 = Malloch | year=2006 |journal=NIME '06 Proceedings of the 2006 Conference on New Interfaces for Musical Expression |publisher=IRCAM – Centre Pompidou|pages=180–183 }}</ref> In those settings, they have been found useful for collaboration on grant writing, [[Social:Strategic planning|strategic planning]], departmental documentation, and committee work.<ref>{{cite journal |title=Putting Wikis to Work in Libraries |first=Nancy T. |last=Lombardo |volume=27 |issue=2 |date=June 2008 |journal=Medical Reference Services Quarterly |pages=129–145 |doi=10.1080/02763860802114223 |pmid = 18844087 |s2cid=11552140 }}</ref> In the mid-2000s, the increasing trend among industries toward collaboration placed a heavier impetus upon educators to make students proficient in collaborative work, inspiring even greater interest in wikis being used in the classroom.<ref name=Legal/>

Wikis have found some use within the legal profession and within the government. Examples include the Central Intelligence Agency's Intellipedia, designed to share and collect [[Intelligence assessment|intelligence]], DKospedia, which was used by the American Civil Liberties Union to assist with review of documents about the internment of detainees in Guantánamo Bay;<ref>{{cite web|url=https://www.dailykos.com/story/2005/06/09/120607/-SusanHu-s-FOIA-Project-UPDATE|title=SusanHu's FOIA Project UPDATE|access-date=June 25, 2013|url-status=live|archive-url=https://web.archive.org/web/20130530181455/https://www.dailykos.com/story/2005/06/09/120607/-SusanHu-s-FOIA-Project-UPDATE|archive-date=May 30, 2013}}</ref> and the wiki of the United States Court of Appeals for the Seventh Circuit, used to post court rules and allow practitioners to comment and ask questions. The United States Patent and Trademark Office operates [[Peer-to-Patent]], a wiki to allow the public to collaborate on finding [[Social:Prior art|prior art]] relevant to the examination of pending patent applications. Queens, New York has used a wiki to allow citizens to collaborate on the design and planning of a local park. Cornell Law School founded a wiki-based legal dictionary called Wex, whose growth has been hampered by restrictions on who can edit.<ref name=Noveck>{{Citation|title=Wikipedia and the Future of Legal Education|last=Noveck|first=Beth Simone|journal=Journal of Legal Education|volume=57|issue=1|url=https://heinonline.org/HOL/LandingPage?collection=journals&handle=hein.journals/jled57&div=8&id=&page=|date=March 2007|url-status=live|archive-url=https://web.archive.org/web/20140703005842/https://heinonline.org/HOL/LandingPage?collection=journals&handle=hein.journals%2Fjled57&div=8&id=&page=|archive-date=July 3, 2014}}{{subscription required}}</ref>

In academic contexts, wikis have also been used as project collaboration and research support systems.<ref>{{Cite book|last=Au|first=C. H.|title=2017 IEEE International Conference on Industrial Engineering and Engineering Management (IEEM) |chapter=Wiki as a research support system — A trial in information systems research |date=December 2017|pages=2271–2275|doi=10.1109/IEEM.2017.8290296|isbn=978-1-5386-0948-4|s2cid=44029462}}</ref><ref>{{Cite web|url=https://www.iaeng.org/publication/WCECS2014/WCECS2014_pp358-363.pdf|title=Using Wiki for Project Collaboration – with Comparison on Facebook|last=Au|first=Cheuk-hang|archive-url=https://web.archive.org/web/20190412152358/https://www.iaeng.org/publication/WCECS2014/WCECS2014_pp358-363.pdf|archive-date=April 12, 2019|url-status=live}}</ref>

===City wikis===
A city wiki (or local wiki) is a wiki used as a [[Knowledge management|knowledge base]] and [[Social:Social network|social network]] for a specific [[Earth:Geography|geographical]] locale.<ref>{{Cite web|last=Andersen |first=Michael |title=Welcome to Davis, Calif.: Six lessons from the world's best local wiki|date=2009-11-06 |url=https://www.niemanlab.org/2009/11/welcome-to-davis-calif-six-lessons-from-the-worlds-best-local-wiki/|access-date=2023-01-06|website=Nieman Lab|archive-date=August 8, 2013|archive-url=https://web.archive.org/web/20130808084426/https://www.niemanlab.org/2009/11/welcome-to-davis-calif-six-lessons-from-the-worlds-best-local-wiki/|url-status=live}}</ref><ref>{{Cite web|last=McGann |first=Laura |title=Knight News Challenge: Is a wiki site coming to your city? Local Wiki will build software to make it simple|date=2010-06-18 |url=https://www.niemanlab.org/2010/06/knight-news-challenge-is-a-wiki-site-coming-to-your-city-local-wiki-will-build-software-to-make-it-simple/|access-date=2023-01-06|website=Nieman Lab|archive-date=June 25, 2013|archive-url=https://web.archive.org/web/20130625035936/https://www.niemanlab.org/2010/06/knight-news-challenge-is-a-wiki-site-coming-to-your-city-local-wiki-will-build-software-to-make-it-simple/|url-status=live}}</ref><ref>Wired: Makice, Kevin (July 15, 2009). [https://archive.wired.com/geekdad/2009/07/hey-kid-support-your-local-wiki/ Hey, Kid: Support Your Local Wiki] {{webarchive|url=https://web.archive.org/web/20150427080359/https://archive.wired.com/geekdad/2009/07/hey-kid-support-your-local-wiki/ |date=April 27, 2015 }}</ref> The term 'city wiki' or its foreign language equivalent (e.g. German 'Stadtwiki') is sometimes also used for wikis that cover not just a city, but a small town or an entire region. A city wiki contains information about specific instances of things, ideas, people and places. Much of this information might not be appropriate for encyclopedias such as Wikipedia (e.g. articles on every retail outlet in a town), but might be appropriate for a wiki with more localized content and viewers. A city wiki could also contain information about the following subjects, that may or may not be appropriate for a general knowledge wiki, such as:
* Details of public establishments such as public houses, bars, accommodation or social centers
* Owner name, opening hours and statistics for a specific shop
* Statistical information about a specific road in a city
* Flavors of ice cream served at a local ice cream parlor
* A biography of a local mayor and other persons

===WikiNodes===
[[File:Development of "Mathe für Nicht-Freaks" from Sep 2009 to June 2016.webm|thumb|Visualization of the collaborative work in
the German wiki project Mathe für Nicht-Freaks]]
WikiNodes are pages on wikis that describe related wikis. They are usually organized as neighbors and delegates. A ''neighbor'' wiki is simply a wiki that may discuss similar content or may otherwise be of interest. A ''delegate'' wiki is a wiki that agrees to have certain content delegated to that wiki.<ref>{{cite web |publisher=WikiNodes |title=Frequently Asked Questions |url=https://wikinodes.wiki.taoriver.net/moin.fcg/FrequentlyAskedQuestions |archive-url=https://web.archive.org/web/20070810213702/https://wikinodes.wiki.taoriver.net/moin.fcg/FrequentlyAskedQuestions |archive-date=August 10, 2007}}</ref> One way of finding a wiki on a specific subject is to follow the wiki-node network from wiki to wiki.

===Participants===
The four basic types of users who participate in wikis are reader, author, wiki administrator and system administrator. The system administrator is responsible for the installation and maintenance of the wiki engine and the container web server. The wiki administrator maintains wiki content and is provided additional functions about pages (e.g. page protection and deletion), and can adjust users' access rights by, for instance, blocking them from editing.<ref>{{cite journal|title=Analysis of the use of Wiki-based collaborations in enhancing student learning|last=Cubric|first=Marija|publisher=University of Hertfordshire|year=2007|url=https://uhra.herts.ac.uk/dspace/handle/2299/3672|access-date=April 25, 2011|url-status=dead|archive-url=https://web.archive.org/web/20110515005430/https://uhra.herts.ac.uk/dspace/handle/2299/3672|archive-date=May 15, 2011 |periodical=UH Business School Working Paper}}</ref>

===Growth factors===
A study of several hundred wikis showed that a relatively high number of administrators for a given content size is likely to reduce growth;<ref>{{cite journal | title = Measuring wiki viability. An empirical assessment of the social dynamics of a large sample of wikis | publisher = The Centre for Research in Social Simulation | first1 = C. | last1 = Roth | first2 = D. | last2 = Taraborelli | first3 = N. | last3 = Gilbert | year = 2008 | page = 3 | quote = Figure 4 shows that having a relatively high number of administrators for a given content size is likely to reduce growth. | url = https://nitens.org/docs/wikidyn.pdf | url-status=live | archive-url = https://web.archive.org/web/20171011105517/https://nitens.org/docs/wikidyn.pdf | archive-date = October 11, 2017 | df = mdy-all |website=nitens.org }}</ref> that access controls restricting editing to registered users tends to reduce growth; that a lack of such access controls tends to fuel new user registration; and that higher administration ratios (i.e. admins/user) have no significant effect on content or population growth.<ref>{{cite journal | title = Measuring wiki viability. An empirical assessment of the social dynamics of a large sample of wikis | publisher = The Centre for Research in Social Simulation | first1 = C. | last1 = Roth | first2 = D. | last2 = Taraborelli | first3 = N. | last3 = Gilbert | year = 2008 | url = https://epubs.surrey.ac.uk:80/1565/1/fulltext.pdf | archive-url = https://web.archive.org/web/20120616204038/https://epubs.surrey.ac.uk/1565/1/fulltext.pdf | url-status=dead | archive-date = June 16, 2012 | access-date = November 9, 2018 | df = mdy-all |website=Surrey Research Insight Open Access }}</ref>

==Conferences==
Active conferences and meetings about wiki-related topics include:
* Atlassian Summit, an annual conference for users of [[Company:Atlassian|Atlassian]] software, including [[Software:Confluence|Confluence]].<ref>{{cite web |url=https://summit.atlassian.com/ |title=Atlassian |publisher=Summit.atlassian.com |access-date=June 20, 2011 |url-status=live |archive-url=https://web.archive.org/web/20110613081406/https://summit.atlassian.com/ |archive-date=June 13, 2011  }}</ref>
* OpenSym (called WikiSym until 2014), an academic conference dedicated to research about wikis and open collaboration.
* SMWCon, a bi-annual conference for users and developers of [[Software:Semantic MediaWiki|Semantic MediaWiki]].<ref>{{cite web |url=https://semantic-mediawiki.org/wiki/SMWCon |title=SMWCon |publisher=Semantic-mediawiki.org |access-date=June 20, 2011 |url-status=live |archive-url=https://web.archive.org/web/20110714183910/https://semantic-mediawiki.org/wiki/SMWCon |archive-date=July 14, 2011  }}</ref>
* TikiFest, a frequently held meeting for users and developers of [[Software:Tiki Wiki CMS Groupware|Tiki Wiki CMS Groupware]].<ref>{{cite web |url=https://tiki.org/TikiFest |title=TikiFest |publisher=Tiki.org |access-date=June 20, 2011 |url-status=live |archive-url=https://web.archive.org/web/20110630070137/https://tiki.org/TikiFest |archive-date=June 30, 2011  }}</ref>
* Wikimania, an annual conference dedicated to the research and practice of [[Organization:Wikimedia Foundation|Wikimedia Foundation]] projects like Wikipedia.

Former wiki-related events include:
* RecentChangesCamp (2006–2012), an unconference on wiki-related topics.
* RegioWikiCamp (2009–2013), a semi-annual unconference on "regiowikis", or wikis on cities and other geographic areas.<ref>{{cite web |url=https://wiki.regiowiki.eu/Main_Page |title=Regiowiki Main Page |publisher=Wiki.regiowiki.eu |access-date=June 20, 2011 |archive-url=https://web.archive.org/web/20090813101324/https://wiki.regiowiki.eu/Main_Page |archive-date=August 13, 2009 |url-status=dead  }}</ref>

==Legal environment==
Joint authorship of articles, in which different users participate in correcting, editing, and compiling the finished product, can also cause editors to become tenants in common of the copyright, making it impossible to republish without permission of all co-owners, some of whose identities may be unknown due to pseudonymous or anonymous editing.<ref name=Legal/> Where persons contribute to a [[Social:Collective work|collective work]] such as an encyclopedia, there is, however, no joint ownership if the contributions are separate and distinguishable.<ref>{{Cite journal|journal=Reports of Patent, Design and Trade Mark Cases|title=Redwood Music Ltd v. B Feldman & Co Ltd and others |doi=10.1093/rpc/1979rpc385 |date=September 1979|url=https://academic.oup.com/rpc/article-abstract/96/18/385/1610864|access-date=|publisher=[[Organization:Oxford University Press|Oxford University Press]]|archive-date=October 17, 2022|archive-url=https://web.archive.org/web/20221017070459/https://academic.oup.com/rpc/article-abstract/96/18/385/1610864|url-status=live}}</ref> Despite most wikis' tracking of individual contributions, the action of contributing to a wiki page is still arguably one of jointly correcting, editing, or compiling, which would give rise to joint ownership. Some copyright issues can be alleviated through the use of an open content license. Version 2 of the [[Software:GNU Free Documentation License|GNU Free Documentation License]] includes a specific provision for wiki relicensing; [[Organization:Creative Commons|Creative Commons]] licenses are also popular. When no license is specified, an implied license to read and add content to a wiki may be deemed to exist on the grounds of business necessity and the inherent nature of a wiki, although the legal basis for such an implied license may not exist in all circumstances.{{citation needed|date=July 2013}}

Wikis and their users can be held liable for certain activities that occur on the wiki. If a wiki owner displays indifference and forgoes controls (such as banning copyright infringers) that they could have exercised to stop copyright infringement, they may be deemed to have authorized infringement, especially if the wiki is primarily used to infringe copyrights or obtains a direct financial benefit, such as advertising revenue, from infringing activities.<ref name=Legal/> In the United States, wikis may benefit from Section 230 of the Communications Decency Act, which protects sites that engage in "Good Samaritan" policing of harmful material, with no requirement on the quality or quantity of such self-policing.<ref>{{cite web | title = Self-Regulation: How Wikipedia Leverages User-Generated Quality Control Under Section 230 | first1 = Kathleen M. | last1 = Walsh | first2 = Sarah | last2 = Oh | date = February 23, 2010 | url = https://works.bepress.com/cgi/viewcontent.cgi?article=1000&context=sarah_oh | url-status=dead | archive-url = https://web.archive.org/web/20140106040705/https://works.bepress.com/cgi/viewcontent.cgi?article=1000&context=sarah_oh | archive-date = January 6, 2014 | df = mdy-all }}</ref> It has also been argued, however, that a wiki's enforcement of certain rules, such as anti-bias, verifiability, reliable sourcing, and no-original-research policies, could pose legal risks.<ref>{{Citation|last = Myers | first = Ken S.|title=Wikimmunity: Fitting the Communications Decency Act to Wikipedia |ssrn-access=free |url=https://papers.ssrn.com/sol3/papers.cfm?abstract_id=916529 |journal=Harvard Journal of Law and Technology|publisher=The Berkman Center for Internet and Society|year=2008|ssrn=916529|volume=20|page=163 |url-status=live |archive-url=https://web.archive.org/web/20240124221800/https://deliverypdf.ssrn.com/delivery.php?ID=256097088074025084113093077025016081116048056043070018004102098070073113118090069100062035127024024056008082071071025106120037047073003040121094126086064082109026009057126000010065095025066118082112066000081066084026080001028089015088099022125003&EXT=pdf&INDEX=TRUE |archive-date= Jan 24, 2024 }}</ref> When defamation occurs on a wiki, theoretically, all users of the wiki can be held liable, because any of them had the ability to remove or amend the defamatory material from the "publication". It remains to be seen whether wikis will be regarded as more akin to an internet service provider, which is generally not held liable due to its lack of control over publications' contents, than a publisher.<ref name=Legal/> It has been recommended that trademark owners monitor what information is presented about their trademarks on wikis, since courts may use such content as evidence pertaining to public perceptions. Joshua Jarvis notes, "Once misinformation is identified, the trademark owner can simply edit the entry".<ref>{{citation|journal=Managing Intellectual Property|volume=No. 179|last=Jarvis|first=Joshua|title=Police your marks in a wiki world|url=https://heinonline.org/HOL/LandingPage?collection=journals&handle=hein.journals/manintpr179&div=31&id=&page=|pages=101–103|date=May 2008|issue=179|url-status=live|archive-url=https://web.archive.org/web/20160304044437/https://heinonline.org/HOL/LandingPage?collection=journals&handle=hein.journals%2Fmanintpr179&div=31&id=&page=|archive-date=March 4, 2016}}</ref>

==See also==
{{div col}}
* [[Software:Comparison of wiki software|Comparison of wiki software]]
* [[Content management system]]
* [[CURIE]]
* [[Philosophy:Dispersed knowledge|Dispersed knowledge]]
* List of wikis
* [[Social:Mass collaboration|Mass collaboration]]
* Sweble
* [[Software:Universal Edit Button|Universal Edit Button]]
* Wikis and education
{{div col end}}

==Notes==
{{reflist|group=note}}

==References==
{{Reflist}}

===Sources===
* {{citation|title=Wiki: Web Collaboration|last=Ebersbach|first= Anja|publisher=[[Company:Springer Science+Business Media|Springer Science+Business Media]]|year=2008|isbn=978-3-540-35150-4}}

==Further reading==
{{refbegin}}
* {{citation|title=Wikipatterns|last=Mader|first=Stewart|publisher={{wipe|John Wiley & Sons}}|date=December 10, 2007|isbn=978-0-470-22362-8|url=https://archive.org/details/wikipatternsapra00made}}
* {{citation|title=Wikinomics: How Mass Collaboration Changes Everything| last = Tapscott | first = Don|publisher=Portfolio Hardcover|date=April 17, 2008|isbn=978-1-59184-193-7| title-link = Mass Collaboration }}
{{refend}}

==External links==
* {{Curlie|Computers/Software/Groupware/Wiki/}}
* [https://www.artima.com/articles/exploring-with-wiki ''Exploring with Wiki''], an interview with [[Biography:Ward Cunningham|Ward Cunningham]] by Bill Verners
* Murphy, Paula (April 2006). [https://web.archive.org/web/20110709101821/https://www.ucop.edu/tltc/news/2006/04/wiki.html Topsy-turvy World of Wiki]. [[Organization:University of California|University of California]].
* [https://c2.com/doc/etymology.html Ward Cunningham's correspondence with etymologists]
* WikiIndex and [https://wikiapiary.com WikiApiary], directories of wikis
* [https://www.wikimatrix.org/ WikiMatrix], a website for comparing wiki software and hosts
* {{GitHub |WikiTeam/wikiteam}}

{{Wiki topics|state=expanded}}
{{Wiki software}}
{{Computer-mediated communication}}


[[Category:Hypertext]]
[[Category:Self-organization]]

{{Sourceattribution|Wiki}}