Citizendium ("CZ") is (was?) 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.
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. By early 2014, only about 10 people made even 10 edits per month. An election held in June 2015 to fill a council seat attracted 13 voters. 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. For context, we're at around 23,000, Conservapedia is around 127,000, and SpaceJam.com, the official website for the titular 1996 live-action Looney Tunes movie featuring former NBA all-star Michael Jordan, ranks 228,000.
In 2020, after years of moribund activity, it was decided that Citizendium in its editable wiki form will close on September 30, 2020, with the possibility of the project living on in another form.