Wikipedia, a free-content online encyclopedia written and maintained by a community of volunteers known as Wikipedians, began with its first edit on 15 January 2001, two days after the domain was registered. It grew out of Nupedia, a more structured free encyclopedia, as a way to allow easier and faster drafting of articles and translations.
A wiki is a form of hypertext publication on the internet which is collaboratively edited and managed by its audience directly through a web browser. A typical wiki contains multiple pages that can either be edited by the public or limited to use within an organization for maintaining its internal knowledge base.
Wiktionary is a multilingual, web-based project to create a free content dictionary of terms in all natural languages and in a number of artificial languages. These entries may contain definitions, images for illustration, pronunciations, etymologies, inflections, usage examples, quotations, related terms, and translations of terms into other languages, among other features. It is collaboratively edited via a wiki. Its name is a portmanteau of the words wiki and dictionary. It is available in 195 languages and in Simple English. Like its sister project Wikipedia, Wiktionary is run by the Wikimedia Foundation, and is written collaboratively by volunteers, dubbed "Wiktionarians". Its wiki software, MediaWiki, allows almost anyone with access to the website to create and edit entries.
MediaWiki is free and open-source wiki software originally developed by Magnus Manske for use on Wikipedia on January 25, 2002, and further improved by Lee Daniel Crocker, after which development has been coordinated by the Wikimedia Foundation. It powers several wiki hosting websites across the Internet, as well as most websites hosted by the Wikimedia Foundation including Wikipedia, Wiktionary, Wikimedia Commons, Wikiquote, Meta-Wiki and Wikidata, which define a large part of the set requirements for the software. Besides its usage on Wikimedia sites, MediaWiki has been used as a knowledge management and content management system on websites such as Fandom, wikiHow and major internal installations like Intellipedia and Diplopedia.
The English Wikipedia is the primary English-language edition of Wikipedia, an online encyclopedia. It was created by Jimmy Wales and Larry Sanger on 15 January 2001, as Wikipedia's first edition.
Wikibooks is a wiki-based Wikimedia project hosted by the Wikimedia Foundation for the creation of free content digital textbooks and annotated texts that anyone can edit.
Wikisource is an online wiki-based digital library of free-content textual sources operated by the Wikimedia Foundation. Wikisource is the name of the project as a whole; it is also the name for each instance of that project, one for each language. The project's aim is to host all forms of free text, in many languages, and translations. Originally conceived as an archive to store useful or important historical texts, it has expanded to become a general-content library. The project officially began on November 24, 2003, under the name Project Sourceberg, a play on Project Gutenberg. The name Wikisource was adopted later that year and it received its own domain name.
The Chinese Wikipedia is the written vernacular Chinese edition of Wikipedia. It was created 11 May 2001. It is one of multiple projects supported by the Wikimedia Foundation.
wikiHow is an online wiki-style publication featuring informational articles and quizzes on a variety of topics. Founded in 2005 by Internet entrepreneur Jack Herrick, its aim is to create an extensive database of instructional content, using the wiki model of open collaboration to allow users to add, create, and modify content. It is a hybrid organization, a for-profit company run for a social mission. wikiHow uses a forked version of the free and open-source MediaWiki software; these modifications made by wikiHow were freely available to the general public via a self-serve download site from 2010 to late 2020, when wikiHow chose to discontinue the self-serve portal, citing vague "DoS attacks", as well as noting that publishing the source code is "not part of our core mission". The site's text content is released under a Creative Commons NonCommercial license.
Wikimapia is a geographic online encyclopedia project. The project implements an interactive "clickable" web map that utilizes Google Maps with a geographically-referenced wiki system, with the aim to mark and describe all geographical objects in the world.
AboutUs.com is an inactive internet domain directory wiki. It lists websites along with information about their content. As a wiki, AboutUs allows Internet users to add entries or modify information. AboutUs.com has since become a wiki for more than just websites. The site allows pages to be created for people, places, and almost anything else.
The Bengali Wikipedia or Bangla Wikipedia is the Bengali language edition of Wikipedia, the free online encyclopedia. Launched on 27 January 2004, it surpassed 10,000 articles in October 2006, becoming the second South-Asian language to do so. On 25 December 2020, the site achieved the milestone of 100,000 articles. As of 14 January 2025, the Bengali Wikipedia has 161,642 articles. Though, it joined later compared to top Wikipedias, it ranks 5th in terms of article depth among 318 active wikipedias by language.
Wikivoyage is a free web-based travel guide for travel destinations and travel topics written by volunteer authors. It is a sister project of Wikipedia and supported and hosted by the same non-profit Wikimedia Foundation (WMF). Wikivoyage has been called the "Wikipedia of travel guides".
Uncyclopedia is the name of several forks of satirical online encyclopedias that parody Wikipedia. Its logo, a hollow "puzzle potato", parodies Wikipedia's globe puzzle logo, and it styles itself as "the content-free encyclopedia", parodying Wikipedia's slogan of "the free encyclopedia" and likely as a play the fact that Wikipedia is described as a "free-content" encyclopedia. Founded in 2005 as an English-language wiki, the project spans more than 75 languages as well as several subprojects parodying other wikis. Uncyclopedia's name is a portmanteau of the prefix un- and the word encyclopedia.
The history of wikis began in 1994, when Ward Cunningham gave the name "WikiWikiWeb" to the knowledge base, which ran on his company's website at c2.com, and the wiki software that powered it. The wiki went public in March 1995, the date used in anniversary celebrations of the wiki's origins. c2.com is thus the first true wiki, or a website with pages and links that can be easily edited via the browser, with a reliable version history for each page. He chose "WikiWikiWeb" as the name based on his memories of the "Wiki Wiki Shuttle" at Honolulu International Airport, and because "wiki" is the Hawaiian word for "quick".
Wikiversity is a Wikimedia Foundation project that supports learning communities, their learning materials, and resulting activities. It differs from Wikipedia in that it offers tutorials and other materials for the fostering of learning, rather than an encyclopedia. It is available in many languages.
Fandom is a wiki hosting service that hosts wikis mainly on entertainment topics. The privately held, for-profit Delaware company was founded in October 2004 by Wikipedia co-founder Jimmy Wales and Angela Beesley. Fandom was acquired in 2018 by TPG Inc. and Jon Miller through Integrated Media Co.
The Wikipedia community, collectively and individually known as Wikipedians, is an online community of volunteers who create and maintain Wikipedia, an online encyclopedia. Since August 2012, the word "Wikipedian" has been an Oxford Dictionary entry. Wikipedians may or may not consider themselves part of the Wikimedia movement, a global network of volunteer contributors to Wikipedia and other related projects hosted by the Wikimedia Foundation.
The following outline is provided as an overview of and a topical guide to Wikipedia:
