Citizendium ("CZ") is a free Internet-based encyclopedia project that began as a pretender to the throne of Wikipedia. Wikipedia co-founder Larry Sanger started the project in 2006 to remedy what he viewed as problems with Wikipedia. It was essentially a reincarnation of the Wikipedia predecessor Nupedia, and just like its previous incarnation, it was a massive failure.
Citizendium aimed to boost its reliability by having articles vetted by experts and requiring contributors to use their real names. Articles were managed by workgroups, which for several years included "healing arts," Citizendium's term for alternative medicine — distinct from the workgroup on "health sciences", medical treatment that actually works. This led to the first public sign that something had gone seriously wrong, when a ludicrous puff piece on homeopathy was featured on the main page in January 2009. While pseudoscience advocates were protected by site policies, many of the recruited academic experts quickly left, driven away by Sanger and the site administrators.
The project began with lofty ambitions and heavy media coverage. Participation grew through early 2008 before entering a steady decline. By June 2011 Citizendium was moribund, with fewer participants and fewer edits than any full month in its history, and with well over half the month's edits made by just three users. It only got worse from then on. 2020 began with a discussion among a handful of people about shutting down the project. Only three people contributed to articles in the first 80 days of 2020.
The project continued essentially as a hobby site for a few individuals who enjoy bureaucracy, Wikipedia-bashing, or believing, despite all evidence to the contrary, that Citizendium is significant (although even these activities underwent a decline) – harmless enough in itself, though unfortunate in its wasted potential. The rise and fall of Citizendium, with issues such as micromanagement, top-heavy organization, and credentialism used to give cranks undue influence, serves as a useful warning to other projects. As of February 2020, the site is currently hovering around the 595,000 mark on Alexa ratings.
In 2020, after years of moribund activity, it was decided that Citizendium in its editable wiki form would close on September 30, 2020, with the possibility of the project living on in another form. However, this did not come to pass, and in 2021 new Citizendium owner Pat Palmer wrote an article redefining the site as a supplement to, and not an alternative to, its main competitor Wikipedia.