The Forge is a heavily moderated forum (in the BBS sense) for the discussion of indie RPGs, created by Ron Edwards and Clinton R. Nixon.
Formerly called Hephaestus' Forge, the Forge is known for high-quality discussion on the nature of role-playing games, including discussion of the controversial "GNS Theory" created by Ron Edwards as a refinement of the threefold model, all in support of creator-owned RPGs.
The Forge also has a reputation of being difficult to understand, pretentious, and elitist. While there is some truth to this charge, it is difficult to avoid being somewhat exclusive if one doesn't want to become the sewer that is RPG.NET, whose forums illustrate the tragedy of the commons all too well. Plus, many of the rules the critics of the Forge decry really amount to common politeness, which the Forge is also known for.