Wikipedia
Wikipedia is a free online encyclopedia written and maintained by a community of volunteers, known as Wikipedians, through open collaboration and the wiki software MediaWiki. Founded by Jimmy Wales and Larry Sanger in 2001, Wikipedia has been hosted since 2003 by the Wikimedia Foundation, an American nonprofit organization funded mainly by donations from readers. Wikipedia is the largest and most-read reference work in history.
Initially available only in English, Wikipedia exists in over 340 languages and is one of the world's most visited websites. The English Wikipedia, with over million articles, remains the largest of the editions, which together comprise more than articles and attract more than 1.5 billion unique device visits and 13 million edits per month as of 2024., over 25% of Wikipedia's traffic comes from the United States, while Japan accounts for nearly 7%, and the United Kingdom, Germany, and Russia each represent around 5%.
Wikipedia has been praised for enabling the democratization of knowledge, its extensive coverage, unique structure, and culture. Wikipedia has been censored by some national governments, ranging from specific pages to the entire site, sometimes due to its criticism of the government or by content otherwise considered blasphemous. Although Wikipedia's volunteer editors have written extensively on a wide variety of topics, the encyclopedia has also been criticized for systemic bias, such as a gender bias against women and a geographical bias against the Global South. While the reliability of Wikipedia was frequently criticized in the 2000s, it has improved over time, receiving greater praise from the late 2010s onward. Articles on breaking news are often accessed as sources for up-to-date information about those events.
History
Nupedia
Various collaborative online encyclopedias were attempted before the start of Wikipedia, but with limited success. 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. 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. 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. Wales is credited with defining the goal of making a publicly editable encyclopedia, while Sanger is credited with the strategy of using a wiki to reach that goal. On January 10, 2001, Sanger proposed on the Nupedia mailing list to create a wiki as a "feeder" project for Nupedia.Launch and growth
Wikipedia was launched on January 15, 2001, as a single English language edition with the domain name www.wikipedia.com, and was announced by Sanger on the Nupedia mailing list. The name, proposed by Sanger to forestall any potential damage to the Nupedia name, originated from a blend of the words wiki and encyclopedia. Its integral policy of "neutral point of view" arose within its first year. Otherwise, there were initially relatively few rules, and it operated independently of Nupedia. Bomis originally intended for it to be a for-profit business.Wikipedia gained early contributors from Nupedia, Slashdot postings, and web search engine indexing. Language editions were created beginning in March 2001, with a total of 161 in use by the end of 2004. Nupedia and Wikipedia coexisted until the former's servers were taken down permanently in 2003, and its text was incorporated into Wikipedia. The English Wikipedia passed the mark of 2 million articles on September 9, 2007, making it the largest encyclopedia ever assembled, surpassing the Yongle Encyclopedia made in China during the Ming dynasty in 1408, which had held the record for almost 600 years.
Due to fears of commercial advertising and lack of control, users of the Spanish Wikipedia forked from Wikipedia to create Enciclopedia Libre in February 2002. Wales then announced that Wikipedia would not display advertisements, and changed Wikipedia's domain from wikipedia.com to wikipedia.org.
After an early period of exponential growth, the growth rate of the English Wikipedia in terms of the numbers of new articles and of editors appears to have peaked around early 2007. The edition reached 3 million articles in August 2009. Around 1,800 articles were added daily to the encyclopedia in 2006; by 2013 that average was roughly 800. A team at the Palo Alto Research Center attributed this slowing of growth to "increased coordination and overhead costs, exclusion of newcomers, and resistance to new edits". Others suggested that the growth flattened naturally because articles that could be called "low-hanging fruit"—topics that clearly merit an article—had already been created and built up extensively.
In November 2009, a researcher at the Rey Juan Carlos University in Madrid, Spain, found that the English Wikipedia had lost 49,000 editors during the first three months of 2009; in comparison, it lost only 4,900 editors during the same period in 2008. The Wall Street Journal cited the array of rules applied to editing and disputes related to such content among the reasons for this trend. Wales disputed these claims in 2009, denying the decline and questioning the study's methodology. Two years later, in 2011, he acknowledged a slight decline, noting a decrease from "a little more than 36,000 writers" in June 2010 to 35,800 in June 2011. In the same interview, he also claimed the number of editors was "stable and sustainable". A 2013 MIT Technology Review article, "The Decline of Wikipedia", questioned this claim, reporting that since 2007 Wikipedia had lost a third of its volunteer editors, and suggesting that those remaining had focused increasingly on minutiae. In July 2012, The Atlantic reported that the number of administrators was also in decline. In November 2013, New York magazine stated, "Wikipedia, the sixth-most-used website, is facing an internal crisis." The number of active English Wikipedia editors has since remained steady after a long period of decline.
On January 20, 2014, Subodh Varma reporting for The Economic Times indicated that not only had Wikipedia's growth stalled, it "had lost nearly ten percent of its page views last year. There was a decline of about 2 billion between December 2012 and December 2013. Its most popular versions are leading the slide: page-views of the English Wikipedia declined by twelve percent, those of German version slid by 17 percent and the Japanese version lost 9 percent." Varma added, "While Wikipedia's managers think that this could be due to errors in counting, other experts feel that Google's Knowledge Graphs project launched last year may be gobbling up Wikipedia users." When contacted on this matter, Clay Shirky, associate professor at New York University and fellow at Harvard's Berkman Klein Center for Internet & Society said that he suspected much of the page-view decline was due to Knowledge Graphs, stating, "If you can get your question answered from the search page, you don't need to click ." By the end of December 2016, Wikipedia was ranked the fifth most popular website globally. As of January 2023, 55,791 English Wikipedia articles have been cited 92,300 times in scholarly journals, from which cloud computing was the most cited page.
Sister projects
Wikipedia has spawned several sister projects, which are also wikis run by the Wikimedia Foundation. These other Wikimedia projects include Wiktionary, a dictionary project launched in December 2002, Wikiquote, a collection of quotations created a week after Wikimedia launched, Wikibooks, a collection of collaboratively written free textbooks and annotated texts, Wikimedia Commons, a site devoted to free-knowledge multimedia, Wikinews, for collaborative journalism, and Wikiversity, a project for the creation of free learning materials and the provision of online learning activities. Another sister project of Wikipedia, Wikispecies, is a catalog of all species, but is not open for public editing. In 2012, Wikivoyage, an editable travel guide, and Wikidata, an editable knowledge base, launched.Milestones
In January 2007, Wikipedia first became one of the ten most popular websites in the United States, according to Comscore Networks. With 42.9 million unique visitors, it was ranked ninth, surpassing The New York Times and Apple. This marked a significant increase over January 2006, when Wikipedia ranked 33rd, with around 18.3 million unique visitors. In 2014, it received 8 billion page views every month. On February 9, 2014, The New York Times reported that Wikipedia had 18 billion page views and nearly 500 million unique visitors a month, "according to the ratings firm comScore"., it ranked sixth in popularity, according to Similarweb. Jeff Loveland and Joseph Reagle argue that, in process, Wikipedia follows a long tradition of historical encyclopedias that have accumulated improvements piecemeal through "stigmergic accumulation".On January 18, 2012, the English Wikipedia participated in a series of coordinated protests against two proposed laws in the United States Congress—the Stop Online Piracy Act and the PROTECT IP Act —by blacking out its pages for 24 hours. More than 162 million people viewed the blackout explanation page that temporarily replaced its content.
In January 2013, 274301 Wikipedia, an asteroid, was named after Wikipedia; in October 2014, Wikipedia was honored with the Wikipedia Monument; and, in July 2015, 106 of the 7,473 700-page volumes of Wikipedia became available as Print Wikipedia. In April 2019, an Israeli lunar lander, Beresheet, crash landed on the surface of the Moon carrying a copy of nearly all of the English Wikipedia engraved on thin nickel plates; experts say the plates likely survived the crash. In June 2019, scientists reported that all 16 GB of article text from the English Wikipedia had been encoded into synthetic DNA.
On January 18, 2023, Wikipedia debuted a new website redesign, called "Vector 2022". It featured a redesigned menu bar, moving the table of contents to the left as a sidebar, and numerous changes in the locations of buttons like the language selection tool. The update initially received backlash, most notably when editors of the Swahili Wikipedia unanimously voted to revert the changes.
Both Sanger and Wales have given public interviews in late 2025 about their reflections about the status and state of Wikipedia leading up to its 25 years of operation on January 15, 2026; Wales appeared on the PBS television news show GZERO World interviewed by Ian Bremmer and Sanger has appeared on the FOX news network interviewed by Ashley Rindsberg. Wales's book The Seven Rules of Trust was published in October 2025 by Penguin Random House. It was described by the publisher as a "sweeping reflection on the global crisis of credibility and knowledge" with the book examining the "rules of trust" that enabled the growth and success of Wikipedia.