Wikipedia[note 3] is a free content online encyclopedia written and maintained by a community of volunteers, known as Wikipedians, through open collaboration and the use of the wiki-based editing system MediaWiki. Wikipedia is the largest and most-read reference work in history.[3][4] It is consistently ranked as one of the ten most popular websites in the world, and as of 2024 is ranked the fifth most visited website on the Internet by Semrush,[5] and second by Ahrefs.[6] Founded by Jimmy Wales and Larry Sanger on January 15, 2001, Wikipedia is hosted by the Wikimedia Foundation, an American nonprofit organization that employs a staff of over 700 people.[7]
Initially only available in English, editions in other languages have been developed. Wikipedia's editions, when combined, comprise more than 62 million articles, attracting around 2 billion unique device visits per month and more than 14 million edits per month (about 5.2 edits per second on average) as of November 2023[update].[8][W 1] Roughly 26% of Wikipedia's traffic is from the United States, followed by Japan at 5.9%, the United Kingdom at 5.4%, Germany at 5%, Russia at 4.8%, and the remaining 54% split among other countries, according to data provided by Similarweb.[9]
Wikipedia has been praised for its enablement of the democratization of knowledge, extent of coverage, unique structure, and culture. It has been criticized for exhibiting systemic bias, particularly gender bias against women and geographical bias against the Global South (Eurocentrism).[10][11][failed verification] While the reliability of Wikipedia was frequently criticized in the 2000s, it has improved over time, receiving greater praise from the late 2010s onward[3][10][12] while becoming an important fact-checking site.[13][14]
Wikipedia has been censored by some national governments, ranging from specific pages to the entire site.[15][16] Articles on breaking news are often accessed as sources for frequently updated information about those events.[17][18]
Various collaborative online encyclopedias were attempted before the start of Wikipedia, but with limited success.[19] Wikipedia began as a complementary project for Nupedia, a free online English-language encyclopedia project whose articles were written by experts and reviewed under a formal process.[20] It was founded on March 9, 2000, under the ownership of Bomis, a web portal company. Its main figures were Bomis CEO Jimmy Wales and Larry Sanger, editor-in-chief for Nupedia and later Wikipedia.[1][21] Nupedia was initially licensed under its own Nupedia Open Content License, but before Wikipedia was founded, Nupedia switched to the GNU Free Documentation License at the urging of Richard Stallman.[W 2] Wales is credited with defining the goal of making a publicly editable encyclopedia,[22][W 3] while Sanger is credited with the strategy of using a wiki to reach that goal.[W 4] On January 10, 2001, Sanger proposed on the Nupedia mailing list to create a wiki as a "feeder" project for Nupedia.[W 5]
The domains wikipedia.org and wikipedia.com (later redirecting to wikipedia.org) were registered on January 13, 2001,[W 6] and January 12, 2001,[W 7] respectively. Wikipedia was launched on January 15, 2001[20] as a single English-language edition at www.wikipedia.com,[W 8] and was announced by Sanger on the Nupedia mailing list.[22] The name originated from a blend of the words wiki and encyclopedia.[23][24] Its integral policy of "neutral point-of-view"[W 9] was codified in its first few months. Otherwise, there were initially relatively few rules, and it operated independently of Nupedia.[22] Bomis originally intended for it to be a for-profit business.[25]
Distribution of the 62,949,954 articles in different language editions (as of May 9, 2024)[W 44]