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.
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.
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 German Wikipedia is the German-language edition of Wikipedia, a free and publicly editable online encyclopedia.
The Danish Wikipedia started on 1 February 2002 and is the Danish language edition of Wikipedia. As of November 2024, it has 303,203 articles and its article depth is 57.52.
The Arabic Wikipedia is the Modern Standard Arabic version of Wikipedia. It started on 9 July 2003. As of November 2024, it has 1,245,657 articles, 2,651,316 registered users and 53,463 files and it is the 17th largest edition of Wikipedia by article count, and ranks 7th in terms of depth among Wikipedias. It was the first Wikipedia in a Semitic language to exceed 100,000 articles on 25 May 2009, and also the first Semitic language to exceed 1 million articles, on 17 November 2019.
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.
Citizendium is an English-language wiki-based free online encyclopedia launched by Larry Sanger, co-founder of Nupedia and Wikipedia.
Lostpedia is a wiki-powered online encyclopedia of information regarding the American television drama Lost. Launched on September 22, 2005, by Kevin Croy, the site uses MediaWiki software to maintain a user-created database of information. The site's content is under a Creative Commons license (by-nc-nd), which means that it is available free to the public, but cannot be used for commercial purposes and should not be modified by people who are not part of the community of the website. As of April 2019, the site contains an estimated 7,380 articles. On December 18, 2008, the site became a part of Wikia.
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".
The Japanese Wikipedia is the Japanese edition of Wikipedia, a free, open-source online encyclopedia. Started on 11 May 2001, the edition attained the 200,000 article mark in April 2006 and the 500,000 article mark in June 2008. As of November 2024, it has almost 1,437,000 articles with 12,553 active contributors, ranking fourth behind the English, French and German editions.
Deletionism and inclusionism are opposing philosophies that largely developed within the community of volunteer editors of the online encyclopedia Wikipedia. The terms reflect differing opinions on the appropriate scope of the encyclopedia and corresponding tendencies either to delete or to include a given encyclopedia article.
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.
The following outline is provided as an overview of and a topical guide to Wikipedia:
Lsjbot is an automated Wikipedia article-creating program, or Wikipedia bot, developed by Sverker Johansson for the Swedish Wikipedia. The bot primarily focuses on articles about living organisms and geographical entities.
Volunteer editors of Wikipedia delete articles from the online encyclopedia regularly, following processes that have been formulated by the site's community over time. The most common route is the outright deletion of articles that clearly violate the rules of the website. Other mechanisms include an intermediate collaborative process that bypasses a complete discussion, and a whole debate at the dedicated forum called Articles for deletion (AfD). As a technical action, deletion can only be done by a subset of editors assigned particular specialized privileges by the community, called administrators. An omission that has been carried out can be contested by appeal to the deleting administrator or on another discussion board called Deletion review (DRV).
The first edit in Wikipedia's database, to HomePage, was made on January 15, 2001, and states in its entirety "This is the new WikiPedia!" In December 2021, co-founder Jimmy Wales announced that he would sell a website containing a re-creation of an earlier edit that he said he made and then later deleted, which contained the text "Hello, World!", to the highest bidder as a non-fungible token (NFT).
