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.

The technological and conceptual underpinnings of Wikipedia predate this; the earliest known proposal for an online encyclopedia was made by Rick Gates in 1993, and the concept of a free-as-in-freedom online encyclopedia (as distinct from mere open source) was proposed by Richard Stallman in 1998.

Stallman's concept specifically included the idea that no central organization should control editing. This contrasted with contemporary digital encyclopedias such as Microsoft Encarta and Encyclopædia Britannica. 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.

While Wikipedia was initially imagined as a place to draft articles and ideas for eventual polishing in Nupedia, it quickly overtook its predecessor, becoming both draft space and home for the polished final product of a global project in hundreds of languages, inspiring a wide range of other online reference projects.

In 2014, Wikipedia had approximately 495 million monthly readers. In 2015, according to comScore, Wikipedia received over 115 million monthly unique visitors from the United States alone. In September 2018, the projects saw 15.5 billion monthly page views.

Historical overview Background The concept of compiling the world's knowledge in a single location dates back to the ancient Library of Alexandria and Library of Pergamum, and there are ancient precursors of the idea of a comprehensive encyclopedia, such as Pliny the Elder's Naturalis historia, but the modern concept of a general-purpose, widely distributed, printed encyclopedia originates with Denis Diderot and the 18th-century French encyclopedists. The idea of using automated machinery beyond the printing press to build a more useful encyclopedia can be traced to Paul Otlet's 1934 book Traité de Documentation. Otlet also founded the Mundaneum, an institution dedicated to indexing the world's knowledge, in 1910. This concept of a machine-assisted encyclopedia was further expanded in H. G. Wells' book of essays World Brain (1938) and Vannevar Bush's future vision of the microfilm-based Memex in his essay "As We May Think" (1945).Reagle, Joseph (2010). Good Faith Collaboration. The Culture of Wikipedia. MIT Press. . Chapter 2: "The Pursuit of the Universal Encyclopedia". Another milestone was Ted Nelson's hypertext design Project Xanadu, which began in 1960.

The use of volunteers was integral in making and maintaining Wikipedia. However, even without the internet, huge complex projects of similar nature had made use of volunteers. 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. It took about 70 years to complete. Dr. Trench envisioned a grand new dictionary of every word in the English language, and to be used democratically and freely. According to author Simon Winchester, "The undertaking of the scheme, he said, was beyond the ability of any one man. To peruse all of English literatureand to comb the London and New York newspapers and the most literate of the magazines and journalsmust be instead 'the combined action of many.' It would be necessary to recruit a teammoreover, a huge oneprobably comprising hundreds and hundreds of unpaid amateurs, all of them working as volunteers."Winchester, Simon (1998). The Professor and the Madman: A Tale of Murder, Insanity, and the Making of the Oxford English Dictionary. Harpers, p. 106.

Advances in information technology in the late 20th century led to changes in the form of encyclopedias. While previous encyclopedias, notably the Encyclopædia Britannica, were often book-based, Microsoft's Encarta, published in 1993, was available on CD-ROM and hyperlinked. The development of the World Wide Web led to many attempts to develop internet encyclopedia projects. An early proposal for an online encyclopedia was Interpedia in 1993 by Rick Gates; this project died before generating any encyclopedic content. Free software proponent Richard Stallman described the usefulness of a "Free Universal Encyclopedia and Learning Resource" in 1998. His published document outlined how to "ensure that progress continues towards this best and most natural outcome."

Wikipedia co-founder Jimmy Wales said that the concept of Wikipedia came when he was a graduate student at Indiana University, where he was impressed with the successes of the open-source movement and found Richard Stallman's Emacs Manifesto promoting free software and a sharing economy interesting. Wales also credits Austrian School economist Friedrich Hayek's essay, "The Use of Knowledge in Society," which he read as an undergraduate, as "central" to his thinking about "how to manage the Wikipedia project." The essay asserts that information is decentralized—that each individual only knows a small fraction of what is known collectively—and that as a result, decisions are best made by those with local knowledge, rather than by a central authority. 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. Richard Stallman discussed at 20min, with further Open Source discussion at 16min. According to The Economist, Wikipedia "has its roots in the techno-optimism that characterised the internet at the end of the 20th century. It held that ordinary people could use their computers as tools for liberation, education, and enlightenment."

Formulation of the concept Wikipedia was initially conceived as a feeder project for the Wales-founded Nupedia, an earlier project to produce a free online encyclopedia, volunteered by Bomis, a web-advertising firm owned by Jimmy Wales, Tim Shell and Michael E. Davis. Nupedia was founded upon the use of qualified volunteer contributors and a considered multi-step peer review process.Kaplan Andreas, Haenlein Michael (2014) Collaborative projects (social media application): About Wikipedia, the free encyclopedia. Business Horizons, Volume 57 Issue 5, pp. 617–626 Despite its mailing list of over 2000 interested editors, and the presence of Sanger as full-time editor-in-chief, the production of content for Nupedia was extremely slow, with only 12 articles written during the first year.

The Nupedians discussed various ways to create content more rapidly. Wikis had been used elsewhere on the web to organize knowledge, and the idea of a wiki-based complement to Nupedia was seeded by a conversation between Sanger and Ben Kovitz, – see also Ben Kovitz' fuller account which he links from there. – While casting around for a way to speed up article production, Sanger met with Kovitz, an old friend, in January 2001. Kovitz introduced Sanger to the idea of the wiki, invented in 1995 by Ward Cunningham: web pages that anyone could write and edit. "My first reaction was that this really could be what would solve the problem," Sanger explains, "because the software was already written, and this community of people on WikiWikiWeb" – the first wiki – "had created something like 14,000 pages". Nupedia, by contrast, had produced barely two dozen articles. Sanger took up the idea immediately: "I wrote up a proposal and sent it [to Wales] that evening, and the wiki was then set up for me to work on." But this was not Wikipedia as we know it. "Originally it was the Nupedia Wiki – our idea was to use it as an article incubator for Nupedia. Articles could begin life on this wiki, be developed collaboratively and, when they got to a certain stage of development, be put into the Nupedia system." and by another between Wales and Jeremy Rosenfeld. Kovitz was a computer programmer and regular on Ward Cunningham's revolutionary wiki "the WikiWikiWeb". He explained to Sanger what wikis were, over a dinner on 2 January 2001. – "Over tacos that night, Sanger explained his concerns about Nupedia's lack of progress, the root cause of which was its serial editorial system. As Nupedia was then structured, no stage of the editorial process could proceed before the previous stage was completed. Kovitz brought up the wiki and sketched out 'wiki magic,' the mysterious process by which communities with common interests work to improve wiki pages by incremental contributions. If it worked for the rambunctious hacker culture of programming, Kovitz said, it could work for any online collaborative project. The wiki could break the Nupedia bottleneck by permitting volunteers to work simultaneously all over the project. With Kovitz in tow, Sanger rushed back to his apartment and called Wales to share the idea. Over the next few days, he wrote a formal proposal for Wales and started a page on Cunningham's wiki called 'Wikipedia." Wales stated in October 2001 that "Larry had the idea to use Wiki software" for people bored by Nupedia process, and later stated in December 2005 that Rosenfeld had introduced him to the wiki concept. Wired.com states: "Wales offered the following on-the-record comment in an e-mail to NewAssignment.net editor [and NYU Professor] Jay Rosen ...' Larry Sanger was my employee working under my direct supervision during the entire process of launching Wikipedia. He was not the originator of the proposal to use a wiki for the encyclopedia project – that was Jeremy Rosenfeld'."Also stated on Wikipedia, on Friday 2 December 2005 permanent reference Stated on Wikipedia on Monday 14 March 2005: reference Sanger thought a wiki would be a good platform to use, and proposed on the Nupedia mailing list that a wiki based upon UseModWiki (then v. 0.90) be set up as a "feeder" project for Nupedia. Under the subject "Let's make a wiki", he wrote:

Wales set one up and put it online on Wednesday 10 January 2001, under the nupedia.com domain. This moved to a new wiki under the wikipedia.com domain on 15 January. On 17 January, the Free Software Foundation's (FSF) GNUPedia project went online, potentially competing with Nupedia, but within a few years the FSF encouraged people "to visit and contribute to [Wikipedia]" instead.

Founding of Wikipedia

There was some hesitation among editors about binding Nupedia too closely to a wiki-style workflow. After a Nupedia wiki was launched under on 10 January 2001, Wales proposed launching the new project under its own name, and Sanger proposed Wikipedia, framing it as "a supplementary project to Nupedia which operates entirely independently." A new wiki was launched at on Monday 15 January 2001. The bandwidth and server (located in San Diego) used for these initial projects were donated by Bomis. Many former Bomis employees later contributed content to the encyclopedia: notably Tim Shell, co-founder and later CEO of Bomis, and programmer Jason Richey.