Other similar communities formed around Blizzard RTS games:

Campaign Creations The Canada to Antioch's US of A. Features campaigns and custom maps for Blizzard games.
StarEdit Network A community for Starcraft mapmakers and modders.
Hive Workshop A hub for Warcraft III custom maps and campaigns, along with editor documentation, tools, and assets.
SC2Mapster The home of Starcraft II custom maps and campaigns, plus a knowledge base and resources for the editor.

Hosted Sites

A number of old community web sites are archived here, to the embarrassment of all involved: