Wikipedia is a Web-based encyclopedia that anyone can contribute to and edit. Contributors are entirely unpaid volunteers who can contribute anonymously or under a pseudonym.
Wikipedia is edited and self-policed to some degree by the community that updates it. However, contributors can be voted into some senior editorial positions by other community members. Certain articles have a "protected" status due to being lightning rods for vandalism or editing wars, and these articles can only be updated by senior editors.
The site was founded in 2001 by Jimmy Wales, who still acts as the senior administrator of the site. Wikipedia is available in many different languages.