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.

In 2001, the license for Nupedia was changed to GFDL, and Jimmy Wales and Larry Sanger launched Wikipedia as a complementary project, using an online wiki as a collaborative drafting tool.

Specifically, the creation of the Oxford English Dictionary was conceived with the speech at the London Library, on Guy Fawkes Day, 5 November 1857, by Richard Chenevix Trench.

Wales also credits Austrian School economist Friedrich Hayek's essay, "The Use of Knowledge in Society," which he read as an undergraduate,[13] as "central" to his thinking about "how to manage the Wikipedia project.

At the time, Wales was studying finance and was intrigued by the incentives of the many people who contributed as volunteers toward creating free software, where many examples were having excellent results.

[20] Despite its mailing list of over 2000 interested editors, and the presence of Sanger as full-time editor-in-chief,[21] the production of content for Nupedia was extremely slow, with only 12 articles written during the first year.

[18] Wikis had been used elsewhere on the web to organize knowledge,[22] and the idea of a wiki-based complement to Nupedia was seeded by a conversation between Sanger and Ben Kovitz,[23][24][25] and by another between Wales and Jeremy Rosenfeld.

[40] The existence of the project was formally announced and an appeal for volunteers to engage in content creation was made to the Nupedia mailing list on 17 January 2001.

[53] The French Wikipedia was created on or around 11 May 2001,[54] in a wave of new language versions that also included Chinese, Dutch, Esperanto, Hebrew, Italian, Portuguese, Russian, Spanish, and Swedish.

Both still supported the open-collaboration concept, but they disagreed on how to handle disruptive editors, specific roles for experts, and the best way to guide the project to success.

As of 2007[update], Wales mostly restricted his role to occasional input on serious matters, executive activity, advocacy of knowledge, and encouragement of similar reference projects.

In 2006 he founded Citizendium, an open encyclopedia that used real names for contributors to reduce disruptive editing, and hoped to facilitate "gentle expert guidance" to increase the accuracy of its content.

[77] The September 11 attacks spurred the appearance of breaking news stories on the homepage, as well as information boxes linking related articles.

[121][122] Jimmy Wales congratulated Knapp for his work and presented him with the site's Special Barnstar medal and the Golden Wiki award for his achievement.

At the start of 2015, Wikipedia remained the largest general-knowledge encyclopedia online, with a combined total of over 36 million mainspace articles across all 291 language editions.

[147] Both Wikipedia's coverage of the COVID-19 pandemic crisis and the supporting edits, discussions, and even deletions were thought to be a useful resource for future historians seeking to understand the period in detail.

[155] MIT Press published an open access book of essays Wikipedia @ 20: Stories of an Unfinished Revolution, edited by Joseph Reagle and Jackie Koerner with contributions from prominent Wikipedians, Wikimedians, researchers, journalists, librarians and other experts reflecting on particular histories and themes.

[158] The new interface received massive critique from users, of many, centered around the fixed width which resulted in an abundance of white space on wide monitors, leading to a 90,000-word-long discussion on whether the new skin should be default, the autumn prior.

Among them, the language selection menu, previously located to the left of the screen, now is found in the top right corner of the display of the article that is currently read.

[171] The search function was also updated in Vector 2022, as the suggested results in response to user queries now include images and short descriptions from the pages in question.

[173][175] The Wikimedia Foundation said that the change was motivated by a desire to modernize the site and improve the navigation and editing experience for readers inexperienced with the internet, as the previous skin was deemed "clunky and overwhelming.

[171][174] Early versions of Vector 2022 first went live in 2020 on the French-, Hebrew-, and Portuguese-language Wikipedia sites,[170] as the skin's new features were rolled out to users for testing gradually before its full release.

[178][172][179] Despite the larger number of editors who expressed that they did not want Vector 2022 to be deployed in its then-current form, as consensus on Wikipedia is not decided by vote, the discussion was closed in favor of the redesign, considering the positive comments left by other users.

[178][172] The Vector 2022 developers made some changes to the skin in response to the criticisms, such as adding a toggle to enable article content to fill the entire width of the screen.

[175][172][174] Annie Rauwerda, creator of the Depths of Wikipedia social media accounts, wrote in Slate that Vector 2022 was not "dramatically different" from the previous skin.

[172] Rauwerda, and Mike Pearl of Mashable, commented that users displeased with the change could weigh in on a discussion about the skin, or use the site's built-in customization features to alter their reading experience.

[229] Upon departure in March 2002, Sanger emphasized the main issue was purely the cessation of funding for his role, which was not viable part-time,[21] and encouraged others to continue contributing to Wikipedia while noting that Nupedia could not survive without a full-time editor-in-chief.

In a separate but similar incident, the campaign manager for Cathy Cox, Morton Brilliant, resigned after being found to have added negative information to the Wikipedia entries of political opponents.

Specialized foreign language forks using the Wikipedia concept include Enciclopedia Libre (Spanish), Wikiweise (German), WikiZnanie (Russian), Susning.nu (Swedish), and Baidu Baike (Chinese).

The German Wikipedia was the first to be partly published also using other media (rather than online on the internet), including releases on CD in November 2004[276] and more extended versions on CDs or DVD in April 2005 and December 2006.