From Mefi Wiki
- SportsFilter is a community weblog for sports fans that runs the same code as MetaFilter but is a separate project.
- MonkeyFilter was created by MeFi lurkers during the period when MetaFilter was closed to new registrations. It began as a haven of sorts for Mefi wannabes to post and comment as they would on Metafilter, if they could only get a membership. Now it's become a community in its own right.
- MetaChat is an informal place for MeFites to touch base and post, discuss and chatter about topics that may not belong on MetaFilter.
- Mefightclub is a gaming community made up of (primarily) Metafilter members, friends and family. Mostly focuses on PC gaming, especially Team Fortress 2, Left 4 Dead, Minecraft and all the rest. Coming up on 5 years old, over 2300 members strong (as of August 2012), it has grown into a network of sites that include the Full Glass Empty Clip group blog and subsites, and The Aporkalypse and Gamefilter, the Metafilter-esque gaming site.
- Big Big Question is a spin-off project launched by cortex Nov 30, 2007, as a home for silly, hypothetical, and other types of questions which would be inappropriate for AskMe. Seemingly kaput as of late December 2010.
- At one time the 5k, an annual contest for websites utilizing fewer than 5Kb of code, was hosted on the MeFi server as well, using much of the same back-end code, but it has since moved.
- 9622.net is a community named after the also infamous 9622 thread. The participants here tend to be more ExMeFite and lurkers than current MeFite regulars, and injokes and chattiness abound. It is a place for people who like people who like MetaFilter, rather than MetaFilter clones.
- PoliticalFilter is another clone, based loosely on the Mefi community model, but all about politics.
- MFCoC is a gaming forum of MeFites dedicated to playing Call of Cthulhu roleplaying game after this MeTa thread.
- Devoter is a group weblog for political topics, including but not limited to US politics. Hasn't really taken off yet.