Geeklog is an open source CMS/weblog application, written in PHP and using MySQL or MS SQL as the database. The current core development group consists of six people, with a further 10-20 people contributing source code, plugins, and other add-ons on a regular basis. The community on www.geeklog.net constantly hovers at around 200 active users, i.e. those that log into the site and participate in discussions. We also have a very active Japanese community that just published the first book about Geeklog.
While Geeklog may be one of the lesser known CMS, it does power a few high-profile sites, e.g. Groklaw, and we also know that it is used quite a bit in company intranets and as a web application framework.
These details are provided for information only. No information here is legal advice and should not be used as such.