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. Initially only available in English, editions in other languages have been developed.

Wikipedia is not a reliable source for citations elsewhere on Wikipedia. As a user-generated source, it can be edited by anyone at any time, and any information it contains at a particular time could be vandalism, a work in progress, or simply incorrect.

The Wikimedia Foundation was established in 2003 in St. Petersburg, Florida by Jimmy Wales, as a nonprofit way to fund Wikipedia, Wiktionary, and other crowdsourced wiki projects. (Until then, they had been hosted by Bomis, Wales's for-profit company.)

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.