|MetaFilter's site and server can always use upgrades of hardware, software, and bandwidth, as well as more stable funding for continued support of its small but high-skilled moderation and backend team! If you'd like to chip in, you can donate to Metafilter.|
MetaFilter itself is written in ColdFusion and runs on IIS. This is not highly portable and to date Matt Haughey has not released the code (although he has tweaked it for other communities). A search for an easy-to-use alternative began as early as 2001. By early 2003 there were three alternatives for those seeking to host their own discussion community using software with the MetaFilter interface and behavior, and available for common webhost configurations.
FreeFilter is written in Perl. It is open source, and the work of Peter Cooper (MeFi ID: wackybrit). Sites running FreeFilter include FilmFilter. FreeFilter is no longer being updated but is still available for downloading.
MetaPhilter (the old domain name appears to have lapsed) is written in PHP, open source, and the work of Jack Driscoll (MeFi userid unknown). There is a conversion tool for FreeFilter. Sites running MetaPhilter include GamesFilter, BookFilter, MusicFilter, LibertyFilter, GyrlFilter, MonkeyFilter, and some personal blogs.
Whedonesque (a.k.a. BuffyFilter) is written in Perl/mySQL, and is the work of prolific. It is officially sanctioned by mathowie, who may have consulted to help tweak the code a bit. Package appears to be not available on site