It is a community of mecha fans. We all participate in a mecha styled, fan-made, forum-based RPG. You can get to use mechas from almost any mecha series under the sun, and you can even make original ones as long as the ideas for them are plausible.
Just take your time to wander around and get a hold of its rules. Even if you don't play in it, you can get to make some educational conversations with the members... XD