Editing MediaWiki (section)

==Key features==
MediaWiki provides a rich core feature set and a mechanism to attach [[Software extension|extension]]s to provide additional functionality.

===Internationalization and localisation===
[[File:Translating the wiki way.webm|thumb|400px|thumbtime=16:00|alt=Niklas Laxström, "Translating the wiki way: Simple, fast, fun", Wikimania 2012|Niklas Laxström explains the features that allowed [[translatewiki.net]] to provide MediaWiki with more than 400 locales.]]

Due to the strong emphasis on multilingualism in the Wikimedia projects, [[internationalization and localization]] has received significant attention by developers. The user interface has been fully or partially translated into more than 400 languages on [[translatewiki.net]],<ref name="translation statistics">{{Cite web |date=2023-08-20 |title=Message group statistics: MediaWiki core |url=https://translatewiki.net/wiki/Special:MessageGroupStats?group=core&messages=&suppressempty=1&x=D#sortable:3=desc |url-status=live |archive-url=https://web.archive.org/web/20230820231524/https://translatewiki.net/wiki/Special:MessageGroupStats?group=core&messages=&suppressempty=1&x=D |archive-date=2023-08-20 |access-date=2023-08-20 |website=translatewiki.net |quote=488 languages (not including languages that are supported but have no translations)}}</ref> and can be further customized by site administrators (the entire interface is editable through the wiki).

Several extensions, most notably those collected in the MediaWiki Language Extension Bundle, are designed to further enhance the multilingualism and internationalization of MediaWiki.

===Installation and configuration===
Installation of MediaWiki requires that the user have [[administrative privileges]] on a server running both PHP and a compatible type of SQL [[#Database|database]]. Some users find that setting up a [[virtual host]] is helpful if the majority of one's site runs under a framework (such as [[Zope]] or [[Ruby on Rails]]) that is largely incompatible with MediaWiki.<ref>{{citation|title=Installing and Customizing MediaWiki|url=https://www.linuxjournal.com/article/8754?page=0,1|last=Lerner|first=Reuven M.|publisher=Linux Journal|date=February 23, 2006|access-date=April 23, 2010|archive-url=https://web.archive.org/web/20100406010012/https://www.linuxjournal.com/article/8754?page=0,1|archive-date=April 6, 2010|url-status=dead}}</ref> [[Cloud hosting]] can eliminate the need to deploy a new server.<ref>{{citation|title=Deploying PHP applications on IBM DB2 in the cloud: MediaWiki as a case study|url=https://portal.acm.org/citation.cfm?id=1723069|last=Petrazickis|first=Leons|publisher=Proceedings of the 2009 Conference of the Center for Advanced Studies on Collaborative Research|year=2009|pages = 304–305|doi = 10.1145/1723028.1723069|s2cid = 27463043|url-access=subscription}}</ref>

An installation PHP script is accessed via a [[web browser]] to initialize the wiki's settings. It prompts the user for a minimal set of required parameters, leaving further changes, such as enabling uploads,<ref>{{cite web |url=https://www.mediawiki.org/wiki/Manual:$wgEnableUploads |title=Manual:$wgEnableUploads |publisher=MediaWiki |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100625234102/https://www.mediawiki.org/wiki/Manual:$wgEnableUploads |archive-date=June 25, 2010 |url-status=live  }}</ref> adding a site logo,<ref>{{cite web |url=https://www.mediawiki.org/wiki/Manual:$wgLogo |title=Manual:$wgLogo |publisher=MediaWiki |date=December 12, 2009 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100625234904/https://www.mediawiki.org/wiki/Manual:$wgLogo |archive-date=June 25, 2010 |url-status=live  }}</ref> and installing extensions, to be made by modifying configuration settings contained in a file called <code>LocalSettings.php</code>.<ref>{{cite web |url=https://www.mediawiki.org/wiki/LocalSettings.php |title=<nowiki>Manual:LocalSettings.php</nowiki> |publisher=MediaWiki |date=March 29, 2007 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100625233619/https://www.mediawiki.org/wiki/LocalSettings.php |archive-date=June 25, 2010 |url-status=live  }}</ref> Some aspects of MediaWiki can be configured through special pages or by editing certain pages; for instance, abuse filters can be configured through a special page,<ref>{{cite web |url=https://www.mediawiki.org/wiki/Extension:AbuseFilter |title=Extension:AbuseFilter |publisher=MediaWiki |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100625224424/https://www.mediawiki.org/wiki/Extension:AbuseFilter |archive-date=June 25, 2010 |url-status=live  }}</ref> and certain gadgets can be added by creating [[JavaScript]] pages in the MediaWiki namespace.<ref name="WikEd">{{cite web| url = https://en.wikipedia.org/wiki/User:Cacycle/wikEd| title = wikEd| author = Cacycle| archive-url = https://web.archive.org/web/20071123151215/https://en.wikipedia.org/wiki/User:Cacycle/wikEd| archive-date = November 23, 2007| url-status = live| df = mdy-all}}</ref> The MediaWiki community publishes a comprehensive installation guide.<ref>{{cite web |url=https://www.mediawiki.org/wiki/Manual:Installation_guide |title=Manual:Installation guide |publisher=MediaWiki |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100625235352/https://www.mediawiki.org/wiki/Manual:Installation_guide |archive-date=June 25, 2010 |url-status=live  }}</ref>

===Markup===
One of the earliest differences between MediaWiki (and its predecessor, [[UseModWiki]]) and other wiki engines was the use of "[[free link]]s" instead of [[CamelCase]]. When MediaWiki was created, it was typical for wikis to require text like "WorldWideWeb" to create a link to a page about the [[World Wide Web]]; links in MediaWiki, on the other hand, are created by surrounding words with double square brackets, and any spaces between them are left intact, e.g. <code>{{brackets|World Wide Web}}</code>. This change was logical for the purpose of creating an encyclopedia, where accuracy in titles is important.

MediaWiki uses an extensible<ref>{{cite web |url=https://www.mediawiki.org/wiki/Manual:Extending_wiki_markup |title=Manual:Extending wiki markup |publisher=MediaWiki |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20110501083425/https://www.mediawiki.org/wiki/Manual:Extending_wiki_markup |archive-date=May 1, 2011 |url-status=live  }}</ref> [[lightweight markup|lightweight]] [[wiki markup]] designed to be easier to use and learn than [[HTML]]. Tools exist for converting content such as [[Table (information)|tables]] between MediaWiki markup and HTML.<ref>{{cite web |url=https://tools.wmflabs.org/magnustools/html2wiki.php |title=HTML to Wiki Converter&nbsp;– tables |publisher=WMF Labs |date=March 29, 2008 |access-date=June 12, 2014 |archive-url=https://web.archive.org/web/20140713040132/https://tools.wmflabs.org/magnustools/html2wiki.php |archive-date=July 13, 2014 |url-status=live  }}</ref> Efforts have been made to create a MediaWiki markup spec, but a consensus seems to have been reached that Wikicode requires [[context-sensitive grammar]] rules.<ref>{{cite web |url=https://www.mediawiki.org/wiki/Markup_spec |title=Markup spec |publisher=MediaWiki |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20071219052149/https://www.mediawiki.org/wiki/Markup_spec |archive-date=December 19, 2007 |url-status=live  }}</ref><ref>{{cite web |url=https://www.cs.rmit.edu.au/adcs2010/proceedings/pdf/paper%204.pdf |title=Extricating Meaning from Wikimedia Article Archives |access-date=January 2, 2011 |archive-url=https://web.archive.org/web/20110310023318/https://www.cs.rmit.edu.au/adcs2010/proceedings/pdf/paper%204.pdf |archive-date=March 10, 2011 |url-status=live  }}</ref> The following side-by-side comparison illustrates the differences between wiki markup and HTML:

{| class="wikitable"
|-
! style="width:300px; height:94px; border-bottom-width:2px"|MediaWiki syntax <br /><span style="font-weight: normal; font-size: 98%">(the "behind the scenes" code<br /> used to add formatting to text)</span>
! style="width:376px; border-bottom-width:2px"|HTML equivalent <br /><span style="font-weight: normal; font-size: 98%">(another type of "behind the scenes" code<br /> used to add formatting to text)</span>
! style="width:230px; border-bottom-width:2px"|Rendered output <br /><span style="font-weight: normal; font-size: 98%">(seen onscreen by a site viewer)</span>
|- style="vertical-align:top;"
|<syntaxhighlight lang="wikitext">

====A dialogue====
"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."</syntaxhighlight>
|<syntaxhighlight lang="html">
<h4>A dialogue</h4>

<p>"Take some more <a href="/wiki/Tea" title="Tea">tea</a>," the March Hare said to Alice, very earnestly.</p> <br>
<p>"I've had nothing yet," Alice replied in an offended tone: "so I can't take more."</p> <br>
<p>"You mean you can't take <i>less</i>," said the Hatter: "it's <b>very</b> easy to take <i>more</i> than nothing."</p></syntaxhighlight>
|<div style="font-weight: bold; margin-top: 24px; margin-bottom: 16px">A dialogue</div>
"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."
|}
<small>(Quotation above from ''[[Alice's Adventures in Wonderland]]'' by [[Lewis Carroll]])</small>

===Editing interface===
{{see also|VisualEditor}}
[[File:MediaWiki 1.44.0-wmf.4 source editing at English Wikipedia screenshot.webp|thumb|upright=1.2|Editing interface of MediaWiki 1.44.0-wmf.4 with [[syntax highlighting]], showing the edit toolbar of 2017 wikitext editor and some examples of wiki syntax]]

MediaWiki's default page-editing tools have been described as somewhat challenging to learn.<ref>{{citation|publisher=Tech & Learning|url=https://www.techlearning.com/article/6164|title=Wild about Wikis|last=Jakes|first=David|date=August 15, 2006|access-date=April 23, 2010|archive-url=https://web.archive.org/web/20100502052101/https://www.techlearning.com/article/6164|archive-date=May 2, 2010|url-status=dead}}</ref> A survey of students assigned to use a MediaWiki-based wiki found that when they were asked an [[Open-ended question|open question]] about main problems with the wiki, 24% cited technical problems with formatting, e.g. "Couldn't figure out how to get an image in. Can't figure out how to show a link with words; it inserts a number."<ref>{{citation|title=Wiki as a professional development tool|first1=Brian|last1=Foley|first2=Tae|last2=Chang|name-list-style=amp|year=2008|publisher=Technology and Teacher Education|url=https://www.csun.edu/~bfoley/AERA_Wiki.pdf|access-date=April 23, 2010|archive-url=https://web.archive.org/web/20110430024752/https://www.csun.edu/~bfoley/AERA_Wiki.pdf|archive-date=April 30, 2011|url-status=live}}</ref>

To make editing long pages easier, MediaWiki allows the editing of a subsection of a page (as identified by its header). A registered user can also indicate whether or not an edit is minor. Correcting spelling, grammar or punctuation are examples of minor edits, whereas adding paragraphs of new text is an example of a non-minor edit.

Sometimes while one user is editing, a second user saves an edit to the same part of the page. Then, when the first user attempts to save the page, an [[edit conflict]] occurs. The second user is then given an opportunity to merge their content into the page as it now exists following the first user's page save.

MediaWiki's user interface has been localized in many different languages. A language for the wiki content itself can also be set, to be sent in the "Content-Language" HTTP header and "lang" [[HTML attribute]].

VisualEditor has its own integrated wikitext editing interface known as 2017 wikitext editor, the older editing interface is known as 2010 wikitext editor.

===Application programming interface===
MediaWiki has an extensible [[web API]] ([[application programming interface]]) that provides direct, high-level access to the data contained in the MediaWiki databases. Client programs can use the API to log in, get data, and post changes. The API supports thin web-based JavaScript clients and end-user applications (such as vandal-fighting tools). The API can be accessed by the [[Front and back ends|backend]] of another web site.<ref>{{cite web |url=https://www.mediawiki.org/wiki/API |title=API |publisher=MediaWiki |date=May 17, 2010 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100527004158/https://www.mediawiki.org/wiki/API |archive-date=May 27, 2010 |url-status=live  }}</ref> An extensive [[Python (programming language)|Python]] [[Internet bot|bot]] library, [[Wikipedia:Pywikibot|Pywikibot]],<ref>{{cite web |url=https://www.mediawiki.org/wiki/Manual:Pywikibot |title=Pywikibot&nbsp;– MediaWiki |publisher=mediawiki.org |access-date=March 16, 2018 |archive-url=https://web.archive.org/web/20180309072418/https://www.mediawiki.org/wiki/Manual:Pywikibot |archive-date=March 9, 2018 |url-status=live  }}</ref> and a popular semi-automated tool called [[Wikipedia:AutoWikiBrowser|AutoWikiBrowser]], also interface with the API.<ref>{{cite web |author=Česky |url=https://en.wikipedia.org/wiki/Wikipedia:AutoWikiBrowser |title=Wikipedia:AutoWikiBrowser&nbsp;– Wikipedia, the free encyclopedia |publisher=En.wikipedia.org |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100420235103/https://en.wikipedia.org/wiki/Wikipedia:AutoWikiBrowser |archive-date=April 20, 2010 |url-status=live  }}</ref> The API is accessed via URLs such as <code><nowiki>https://en.wikipedia.org/w/api.php?action=query&list=recentchanges</nowiki></code>. In this case, the query would be asking Wikipedia for information relating to the last 10 edits to the site. One of the perceived advantages of the API is its language independence; it listens for [[HTTP]] connections from clients and can send a response in a variety of formats, such as [[XML]], serialized PHP, or [[JSON]].<ref>{{citation|title=Facilitating Wiki/Repository Communication with Metadata|url=https://smartech.gatech.edu/dspace/handle/1853/28426|author1=Bartolo, Laura M.|author2=Lowe, Cathy S.|author3=Songar, Poonam|author4=Tandy, Robert J.|date=May 20, 2009|publisher=Georgia Institute of Technology|access-date=April 23, 2010|archive-url=https://web.archive.org/web/20110109004041/https://smartech.gatech.edu/dspace/handle/1853/28426|archive-date=January 9, 2011|url-status=dead}}</ref> [[Client–server model|Client code]] has been developed to provide layers of [[abstraction (computer science)|abstraction]] to the API.<ref>{{cite web |url=https://www.mediawiki.org/wiki/API:Client_code |title=API:Client code |publisher=MediaWiki |date=May 24, 2010 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100626072508/https://www.mediawiki.org/wiki/API:Client_code |archive-date=June 26, 2010 |url-status=live  }}</ref>

===Tracking edits===
Among the features of MediaWiki to assist in tracking edits is a Recent Changes feature that provides a list of recent edits to the wiki. This list contains basic information about those edits such as the editing user, the edit summary, the page edited, as well as any tags (e.g. "possible [[Vandalism on Wikipedia|vandalism]]")<ref>{{cite web |url=https://en.wikipedia.org/wiki/Special:Tags |title=Tags&nbsp;– Wikipedia, the free encyclopedia |publisher=En.wikipedia.org |access-date=May 30, 2010 |archive-date=March 4, 2010 |archive-url=https://web.archive.org/web/20100304112922/https://en.wikipedia.org/wiki/Special:Tags |url-status=live }}</ref> added by customizable abuse filters and other extensions to aid in combating unhelpful edits.<ref>{{cite web |url=https://www.mediawiki.org/wiki/Manual:Tags |title=Manual:Tags |publisher=MediaWiki |date=August 31, 2009 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100625224408/https://www.mediawiki.org/wiki/Manual:Tags |archive-date=June 25, 2010 |url-status=live  }}</ref> On more active wikis, so many edits occur that it is hard to track Recent Changes manually. Anti-vandal software, including user-assisted tools,<ref>{{cite web |url=https://en.wikipedia.org/wiki/Wikipedia:Huggle |title=Wikipedia:Huggle&nbsp;– Wikipedia, the free encyclopedia |publisher=En.wikipedia.org |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20110331172521/https://en.wikipedia.org/wiki/Wikipedia:Huggle |archive-date=March 31, 2011 |url-status=live  }}</ref> is sometimes employed on such wikis to process Recent Changes items. Server load can be reduced by sending a continuous feed of Recent Changes to an [[IRC channel]] that these tools can monitor, eliminating their need to send requests for a refreshed Recent Changes feed to the API.<ref>{{cite web |url=https://meta.wikimedia.org/wiki/IRC/Channels#Raw_feeds |title=IRC/Channels |publisher=Meta-Wiki |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100323020404/https://meta.wikimedia.org/wiki/IRC/Channels#Raw_feeds#Raw_feeds |archive-date=March 23, 2010 |url-status=live  }}</ref><ref>{{cite web| url= https://www.bbc.co.uk/news/magazine-18892510| title= Meet the 'bots' that edit Wikipedia| author= Daniel Nasaw| work= BBC News| date= July 25, 2012| access-date= July 30, 2012| archive-url= https://web.archive.org/web/20120728024625/https://www.bbc.co.uk/news/magazine-18892510| archive-date= July 28, 2012| url-status= live| df= mdy-all}}</ref>

Another important tool is watchlisting. Each logged-in user has a watchlist to which the user can add whatever pages he or she wishes. When an edit is made to one of those pages, a summary of that edit appears on the watchlist the next time it is refreshed.<ref>{{cite web |url=https://www.mediawiki.org/wiki/Manual:Watchlist |title=Manual:Watchlist |publisher=MediaWiki |date=November 24, 2009 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20110501081950/https://www.mediawiki.org/wiki/Manual:Watchlist |archive-date=May 1, 2011 |url-status=live  }}</ref> As with the recent changes page, recent edits that appear on the watchlist contain clickable links for easy review of the article history and specific changes made.

There is also the capability to review all edits made by any particular user. In this way, if an edit is identified as problematic, it is possible to check the user's other edits for issues.

MediaWiki allows one to link to specific versions of articles. This 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>{{citation|title=Wiki ware could harness the Internet for science|author=Kevin Yager|journal=Nature|date=March 16, 2006|volume=440|issue=7082|doi=10.1038/440278a|pages=278|pmid=16541049|bibcode=2006Natur.440..278Y|doi-access=free}}</ref>

===Navigation===

==== Wikilinks ====
Navigation through the wiki is largely through internal wikilinks. MediaWiki's wikilinks implement page existence detection, in which a link is colored blue if the target page exists on the local wiki and red if it does not. If a user clicks on a red link, they are prompted to create an article with that title. Page existence detection makes it practical for users to create "wikified" articles—that is, articles containing links to other pertinent subjects—without those other articles being yet in existence.

==== Interwiki links ====
{{redirect|selfref=true|Inter-wiki link|help with interwiki linking on Wikipedia|Help:Interwiki linking}}
Interwiki links function much the same way as namespaces. A set of interwiki prefixes can be configured to cause, for instance, a page title of <code>wikiquote:Jimbo Wales</code> to direct the user to the Jimbo Wales article on [[Wikiquote]].<ref>{{cite web |url=https://www.mediawiki.org/wiki/Manual:Interwiki |title=Manual:Interwiki |publisher=MediaWiki |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20101203112631/https://www.mediawiki.org/wiki/Manual:Interwiki |archive-date=December 3, 2010 |url-status=live  }}</ref> Unlike internal wikilinks, interwiki links lack page existence detection functionality, and accordingly there is no way to tell whether a blue interwiki link is broken or not.

==== Interlanguage links ====
[[File:Interlanguage links prior to Wikidata.png|thumb|An example of interlanguage links]]
Interlanguage links are the small navigation links that show up in the sidebar in most MediaWiki skins that connect an article with related articles in other languages within the same Wiki family. This can provide language-specific communities connected by a larger context, with all wikis on the same server or each on its own server.<ref>{{Cite web|title=Interlanguage links|url=https://www.mediawiki.org/wiki/Interlanguage_links|url-status=live|access-date=March 17, 2021|website=MediaWiki|language=en|archive-date=March 12, 2021|archive-url=https://web.archive.org/web/20210312133505/https://www.mediawiki.org/wiki/Interlanguage_links}}</ref>

Previously, Wikipedia used interlanguage links to link an article to other articles on the same topic in other editions of Wikipedia. This was superseded by the launch of Wikidata.<ref>{{Cite web|last=Pintscher|first=Lydia|date=September 23, 2013|title=Wikidata is Here!|url=https://commons.wikimedia.org/wiki/Commons:Village_pump/Archive/2013/10#Wikidata_is_here.21|url-status=live|access-date=March 17, 2021|website=[[Commons:Commons:Village pump|Commons:Village pump]]|language=en|archive-date=December 6, 2021|archive-url=https://web.archive.org/web/20211206060438/https://commons.wikimedia.org/wiki/Commons:Village_pump/Archive/2013/10#Wikidata_is_here.21}}</ref>

===Content organization===

====Page tabs and associated pages====
[[File:MediaWiki Vector skin tabs.png|frame|MediaWiki page tabs, using the "Vector 2010" skin. The red coloration of the "discussion" tab indicates that the article does not yet have a talk page. As with any other red wikilink, clicking on it prompts the user to create the page.]]
Page tabs are displayed at the top of pages. These tabs allow users to perform actions or view pages that are related to the current page. The available default actions include viewing, editing, and discussing the current page. The specific tabs displayed depend on whether the user is logged into the wiki and whether the user has sysop privileges on the wiki. For instance, the ability to move a page or add it to one's watchlist is usually restricted to logged-in users. The site administrator can add or remove tabs by using JavaScript or installing extensions.<ref>{{cite web |url=https://www.mediawiki.org/wiki/Help:Navigation#Page_Tabs |title=Help:Navigation |publisher=MediaWiki |date=May 21, 2010 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100527004218/https://www.mediawiki.org/wiki/Help:Navigation#Page_Tabs#Page_Tabs |archive-date=May 27, 2010 |url-status=live  }}</ref>

Each page has an associated history page from which the user can access every version of the page that has ever existed and generate [[diff]]s between two versions of his choice. Users' contributions are displayed not only here, but also via a "user contributions" option on a sidebar. In a 2004 article, Carl Challborn and Teresa Reimann noted that "While this feature may be a slight deviation from the collaborative, 'ego-less' spirit of wiki purists, it can be very useful for educators who need to assess the contribution and participation of individual student users."<ref>{{citation|url=https://cde.athabascau.ca/softeval/reports/R470412.pdf|title=Wiki products: a comparison|author1=Carl Challborn|author2=Teresa Reimann|name-list-style=amp|date=December 2004|publisher=Athabasca University|access-date=April 23, 2010|archive-url=https://web.archive.org/web/20101223221302/https://cde.athabascau.ca/softeval/reports/R470412.pdf|archive-date=December 23, 2010|url-status=live}}</ref>

==== {{anchor|Talk page|Namespace}} Namespaces ====
{{redirect|selfref=true|Talk page|talk pages on Wikipedia|Help:Talk pages}}

MediaWiki provides many features beyond [[hyperlink]]s for structuring content. One of the earliest such features is ''[[namespace]]s''. One of Wikipedia's earliest problems had been the separation of encyclopedic content from pages pertaining to maintenance and communal discussion, as well as personal pages about encyclopedia editors. Namespaces are prefixes before a page title (such as "<code>User:</code>" or "<code>Talk:</code>") that serve as descriptors for the page's purpose and allow multiple pages with different functions to exist under the same title. For instance, a page titled "<code>{{brackets|The Terminator}}</code>", in the default namespace, could describe [[The Terminator|the 1984 movie]] starring [[Arnold Schwarzenegger]], while a page titled "<code>{{brackets|User:The Terminator}}</code>" could be a profile describing a user who chooses this name as a pseudonym. More commonly, each namespace has an associated "<code>Talk:</code>" namespace, which can be used to discuss its contents, such as "<code>User talk:</code>" or "<code>Template talk:</code>". The purpose of having discussion pages is to allow content to be separated from discussion surrounding the content.<ref>{{cite book |title=Enterprise 2. 0 Implementation |last1=Newman |first1=Aaron |first2=Adam |last2=Steinberg |first3=Jeremy |last3=Thomas |page=185 |publisher=McGraw-Hill Professional |year=2008 |isbn=978-0-07-159160-7}}</ref><ref>{{cite book |title=Multi-Stakeholder Governance and the Internet Governance Forum |url=https://archive.org/details/multistakeholder00malc |url-access=limited |author=Malcolm, Jeremy |pages=[https://archive.org/details/multistakeholder00malc/page/n216 188], 280 |publisher=Terminus Press |year=2008 |isbn=978-0-9805084-0-6}}</ref>

Namespaces can be viewed as [[file folder|folders]] that separate different basic types of information or functionality. Custom namespaces can be added by the site administrators. There are 16 namespaces by default for content, with 2 "pseudo-namespaces" used for dynamically generated "<code>Special:</code>" pages and links to media files. Each namespace on MediaWiki is numbered: content page namespaces have even numbers and their associated talk page namespaces have odd numbers.<ref>{{cite book|title=Wiki |url=https://archive.org/details/wikiwebcollabora00eber_531 |url-access=limited |last1=Ebersbach |first1=Anja |first2=Markus |last2=Glaser |first3=Richard |last3=Heigl |first4=Gunter |last4=Dueck |pages=[https://archive.org/details/wikiwebcollabora00eber_531/page/n68 55], 80–82, 109, 120–121, 156 |publisher=Springer |year=2006 |isbn=978-3-540-25995-4}}</ref>

====Category tags====
Users can create new categories and add pages and files to those categories by appending one or more category tags to the content text. Adding these tags creates links at the bottom of the page that take the reader to the list of all pages in that category, making it easy to browse related articles.<ref>{{cite web |url=https://www.mediawiki.org/wiki/Help:Categories |title=Help:Categories |publisher=MediaWiki |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100625220958/https://www.mediawiki.org/wiki/Help:Categories |archive-date=June 25, 2010 |url-status=live  }}</ref> The use of categorization to organize content has been described as a combination of:
* [[Social bookmarking|Collaborative tagging systems]] like [[del.icio.us]] and
* [[Library classification|Hierarchical classifications]] like the [[Dewey Decimal Classification]].<ref>{{cite arXiv|title=Collaborative thesaurus tagging the Wikipedia way|eprint=cs.IR/0604036|date=April 27, 2006|author=Jakob Voss}}</ref>

====Subpages====
In addition to namespaces, content can be ordered using ''subpages''. This simple feature provides automatic [[breadcrumb (navigation)|breadcrumbs]] of the pattern <code>{{brackets|Page title/Subpage title}}</code> from the page after the slash (in this case, "Subpage title") to the page before the slash (in this case, "Page title").

===Customization===
[[File:Popup-preview.png|thumb|Users can configure custom [[JavaScript]] that is executed on every pageview. This has led to JavaScript tools that users can "install", the "navigation popups" tool shown here displays a small preview of an article when hovering over a link title.]]

If the feature is enabled, users can customize their stylesheets and configure [[client-side JavaScript]] to be executed with every pageview. On Wikipedia, this has led to a large number of additional tools and helpers developed through the wiki and shared among users. For instance, ''navigation popups'' is a custom JavaScript tool that shows previews of articles when the user hovers over links and also provides shortcuts for common maintenance tasks.<ref>{{cite web| url = https://en.wikipedia.org/wiki/Wikipedia:Tools/Navigation_popups| title = Wikipedia:Tools/Navigation popups| author = Lupin| archive-url = https://web.archive.org/web/20060718164504/https://en.wikipedia.org/wiki/Wikipedia%3ATools/Navigation_popups| archive-date = July 18, 2006| url-status = live| df = mdy-all}}</ref>

[[File:Screenshot-skin-material.png|thumb|A [[screenshot]] of a wiki using MediaWiki with a customized skin]]

The entire MediaWiki user interface can be edited through the wiki itself by users with the necessary permissions (typically called "administrators"). This is done through a special namespace with the prefix "MediaWiki:", where each page title identifies a particular user interface message. Using an extension,<ref>{{cite web |url=https://www.mediawiki.org/wiki/Extension:Gadgets |title=Extension:Gadgets |publisher=MediaWiki |date=March 30, 2010 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100625220327/https://www.mediawiki.org/wiki/Extension:Gadgets |archive-date=June 25, 2010 |url-status=live  }}</ref> it is also possible for a user to create personal scripts, and to choose whether certain sitewide scripts should apply to them by toggling the appropriate options in the user preferences page.

===Templates===
The "MediaWiki:" namespace was originally also used for creating custom text blocks that could then be dynamically loaded into other pages using a special syntax. This content was later moved into its own namespace, "Template:".

Templates are text blocks that can be dynamically loaded inside another page whenever that page is requested. The template is a special link in double [[curly bracket]]s (for example "<code><nowiki>{{Disputed|date=October 2018}}</nowiki></code>"), which calls the template (in this case located at {{self-reference link|Template:Disputed}}) to load in place of the template call.

Templates are [[structured document]]s containing [[attribute–value pair]]s. They are defined with [[parameter]]s, to which are assigned [[Value (computer science)|values]] when [[transclusion|transcluded]] on an article page. The name of the parameter is [[Delimiter|delimited]] from the value by an [[equals sign]]. A class of templates known as [[infobox]]es is used on Wikipedia to collect and present a subset of information about its subject, usually on the top (mobile view) or top right-hand corner (desktop view) of the document.

Pages in other namespaces can also be transcluded as templates. In particular, a page in the main namespace can be transcluded by prefixing its title with a colon; for example, <code>{{((}}:MediaWiki{{))}}</code> transcludes the article "MediaWiki" from the main namespace. Also, it is possible to mark the portions of a page that should be transcluded in several ways, the most basic of which are:<ref>{{Cite conference |last=Anderson |first=Mark |last2=Carr |first2=Leslie |last3=Millard |first3=David E. |date=2017-07-04 |title=There and Here: Patterns of Content Transclusion in Wikipedia |url=https://dl.acm.org/doi/10.1145/3078714.3078726 |language=en |conference=28th ACM Conference on Hypertext and Social Media |location=Prague, Czech Republic |publisher=ACM |pages=115–124 |doi=10.1145/3078714.3078726 |isbn=978-1-4503-4708-2}}</ref>

* {{tag|noinclude}}, which marks content that is not to be transcluded;
* {{tag|includeonly}}, which marks content that is not rendered unless it is transcluded;
* {{tag|onlyinclude}}, which marks content that is to be the ''only'' content transcluded.

A related method, called template ''substitution'' (called by adding <code>subst:</code> at the beginning of a template link) inserts the contents of the template into the target page (like a [[copy and paste]] operation), instead of loading the template contents dynamically whenever the page is loaded. This can lead to inconsistency when using templates, but may be useful in certain cases, and in most cases requires fewer [[server (computing)|server]] resources (the actual amount of savings can vary depending on wiki configuration and the complexity of the template).

Templates have found many different uses. Templates enable users to create complex table layouts that are used consistently across multiple pages, and where only the content of the tables gets inserted using template parameters. Templates are frequently used to identify problems with a Wikipedia article by putting a template in the article. This template then outputs a graphical box stating that the article content is disputed or in need of some other attention, and also categorize it so that articles of this nature can be located. Templates are also used on user pages to send users standard messages welcoming them to the site,<ref>{{cite web |author=Česky |url=https://en.wikipedia.org/wiki/Template:Welcome |title=Template:Welcome&nbsp;– Wikipedia, the free encyclopedia |publisher=En.wikipedia.org |date=May 16, 2010 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20110506003930/https://en.wikipedia.org/wiki/Template:Welcome |archive-date=May 6, 2011 |url-status=live  }}</ref> giving them awards for outstanding contributions,<ref>{{citation|url=https://portal.acm.org/citation.cfm?id=1460563.1460573|publisher=Proceedings of the ACM|author1=T Kriplean |author2=I Beschastnikh | title=Proceedings of the 2008 ACM conference on Computer supported cooperative work | chapter=Articulations of wikiwork: Uncovering valued work in wikipedia through barnstars |year=2008|pages = 47–56|doi = 10.1145/1460563.1460573|isbn = 9781605580074|s2cid = 7164949|display-authors=etal|url-access=subscription}}</ref><ref>{{cite web |author=Česky |url=https://en.wikipedia.org/wiki/Wikipedia:Barnstars |title=Wikipedia:Barnstars&nbsp;– Wikipedia, the free encyclopedia |publisher=En.wikipedia.org |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20090624134612/https://en.wikipedia.org/wiki/Wikipedia:Barnstars |archive-date=June 24, 2009 |url-status=live  }}</ref> warning them when their behavior is considered inappropriate,<ref>{{cite web |author=Česky |url=https://en.wikipedia.org/wiki/Template:Test |title=Template:Test&nbsp;– Wikipedia, the free encyclopedia |publisher=En.wikipedia.org |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20091111014442/https://en.wikipedia.org/wiki/Template:Test |archive-date=November 11, 2009 |url-status=live  }}</ref> notifying them when they are blocked from editing,<ref>{{cite web |url=https://en.wikipedia.org/wiki/Template:Test5 |title=Template:Test5&nbsp;– Wikipedia, the free encyclopedia |publisher=En.wikipedia.org |date=June 19, 2008 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20090424005115/https://en.wikipedia.org/wiki/Template:Test5 |archive-date=April 24, 2009 |url-status=live  }}</ref> and so on.

===Groups and restriction of access===
MediaWiki offers flexibility in creating and defining user groups. For instance, it would be possible to create an arbitrary "ninja" group that can block users and delete pages, and whose edits are hidden by default in the recent changes log. It is also possible to set up a group of "autoconfirmed" users that one becomes a member of after making a certain number of edits and waiting a certain number of days.<ref>{{cite web |url=https://www.mediawiki.org/wiki/Manual:User_rights_management#Automatically_promote_users |title=Manual:User rights management |publisher=MediaWiki |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100625222112/https://www.mediawiki.org/wiki/Manual%3AUser_rights_management#Automatically_promote_users#Automatically_promote_users |archive-date=June 25, 2010 |url-status=live  }}</ref> Some groups that are enabled by default are bureaucrats and sysops. Bureaucrats have the power to change other users' rights. Sysops have power over page protection and [[Deletion of articles on Wikipedia|deletion]] and the blocking of users from editing. MediaWiki's available controls on editing rights have been deemed sufficient for publishing and maintaining important documents such as a manual of [[standard operating procedures]] in a hospital.<ref>{{citation|title=Operating Procedures in Clinical Practice|author1=H Zielke|author2=W Boemke|author3=M Kastrup|author4=C Melzer|publisher=Royal College of Anaesthetists|url=https://www.scata.org.uk/abstracts/2007_london/DelegateBookletSCATALondon2007.pdf|date=November 21, 2007|access-date=April 25, 2010|archive-url=https://web.archive.org/web/20110515020030/https://www.scata.org.uk/abstracts/2007_london/DelegateBookletSCATALondon2007.pdf|archive-date=May 15, 2011|url-status=live}}</ref>

MediaWiki comes with a basic set of features related to restricting access, but its original and ongoing design is driven by functions that largely relate to content, not content segregation. As a result, with minimal exceptions (related to specific tools and their related "Special" pages), page access control has never been a high priority in core development and developers have stated that users requiring secure user access and authorization controls should not rely on MediaWiki, since it was never designed for these kinds of situations. For instance, it is extremely difficult to create a wiki where only certain users can read and access some pages.<ref>{{cite web |url=https://www.mediawiki.org/wiki/Security_issues_with_authorization_extensions |title=Security issues with authorization extensions |publisher=MediaWiki |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20100626074354/https://www.mediawiki.org/wiki/Security_issues_with_authorization_extensions |archive-date=June 26, 2010 |url-status=live  }}</ref> Here, wiki engines like [[Foswiki]], [[MoinMoin]] and [[Confluence (software)|Confluence]] provide more flexibility by supporting advanced security mechanisms like [[access control list]]s.

===Extensibility===
The MediaWiki codebase contains various [[Hooking|hooks]] using [[callback (computer science)|callback]] [[Subroutine|functions]] to add additional PHP code in an [[Extensibility|extensible]] way. This allows developers to write extensions without necessarily needing to modify the core or having to submit their code for review. Installing an extension typically consists of adding a line to the configuration file, though in some cases additional changes such as database updates or core patches are required.

Five main extension points were created to allow developers to add features and functionalities to MediaWiki. Hooks are run every time a certain event happens; for instance, the <code>ArticleSaveComplete</code> hook occurs after a save article request has been processed.<ref>{{cite web |url=https://www.mediawiki.org/wiki/Manual:Hooks/ArticleSaveComplete |title=Manual:Hooks/ArticleSaveComplete |publisher=MediaWiki |date=May 26, 2010 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20141110145905/https://www.mediawiki.org/wiki/Manual:Hooks/ArticleSaveComplete |archive-date=November 10, 2014 |url-status=live  }}</ref> This can be used, for example, by an extension that notifies selected users whenever a page edit occurs on the wiki from new or anonymous users.<ref>{{cite web |url=https://www.mediawiki.org/wiki/Extension:Recent_Activity_Notify |title=Extension:Recent Activity Notify |publisher=MediaWiki |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20140927110023/https://www.mediawiki.org/wiki/Extension:Recent_Activity_Notify |archive-date=September 27, 2014 |url-status=live  }}</ref> New tags can be created to process data with opening and closing tags (<code><newtag>...</newtag></code>).<ref>{{cite web |url=https://www.mediawiki.org/wiki/Manual:Tag_extensions |title=Manual:Tag extensions |publisher=MediaWiki |date=May 21, 2010 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20141012211540/https://www.mediawiki.org/wiki/Manual:Tag_extensions |archive-date=October 12, 2014 |url-status=live  }}</ref> Parser functions can be used to create a new command (<code><nowiki>{{#if:...|...|...}}</nowiki></code>).<ref>{{cite web |url=https://www.mediawiki.org/wiki/Manual:Parser_functions |title=Manual:Parser functions |publisher=MediaWiki |date=March 22, 2010 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20141018103626/https://www.mediawiki.org/wiki/Manual:Parser_functions |archive-date=October 18, 2014 |url-status=live  }}</ref> New special pages can be created to perform a specific function. These pages are dynamically generated. For example, a special page might show all pages that have one or more links to an external site or it might create a form providing user submitted feedback.<ref>{{cite web |url=https://www.mediawiki.org/wiki/Manual:Special_pages |title=Manual:Special pages |publisher=MediaWiki |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20141110162401/https://www.mediawiki.org/wiki/Manual:Special_pages |archive-date=November 10, 2014 |url-status=live  }}</ref> [[Skin (computing)|Skins]] allow users to customize the look and feel of MediaWiki.<ref>{{cite web |url=https://www.mediawiki.org/wiki/Skin |title=Manual:Skins |publisher=MediaWiki |date=May 14, 2010 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20141125085917/https://www.mediawiki.org/wiki/Skin |archive-date=November 25, 2014 |url-status=live  }}</ref> A minor extension point allows the use of [[Amazon S3]] to host image files.<ref>{{cite web |url=https://www.mediawiki.org/wiki/Manual:Integration_with_S3 |title=Manual:Integration with S3 |publisher=MediaWiki |date=March 22, 2010 |access-date=May 30, 2010 |archive-url=https://web.archive.org/web/20141127084520/https://www.mediawiki.org/wiki/Manual:Integration_with_S3 |archive-date=November 27, 2014 |url-status=live  }}</ref>