There’s a clever new map on ENWorld that takes all the RPG forums, and at one hex per 1000 users, turns them into a fantasy world map. It’s interesting to see the relative sizes. ENWorld, RPG.net, and WotC are all big, but there’s some big ones I’ve never heard of – what’s a “Myth Weavers?” And Giant In The Playground is a lot bigger than I thought. Anyway, it’s good fun, and might lead you to some fun new forums, so check it out!
Geek Speak
Geek Related 
Myth Weavers is a play by post focuses forum site. FYI.
I see a number of forums that I haven’t heard of before. Interesting. I no longer visit either WotC or EN World however. Once the shift to 4E took place I no longer felt welcome. One I do like is the 3.5 Private Sanctuary.