Other similar communities formed around Blizzard RTS games:

Campaign CreationsThe Canada to Antioch's US of A. Features campaigns and custom maps for Blizzard games.
StarEdit NetworkA community for Starcraft mapmakers and modders.
Hive WorkshopA hub for Warcraft III custom maps and campaigns, along with editor documentation, tools, and assets.
SC2MapsterThe 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: