It is a voice over IP chat room basically. Pretty much was designed so that you could get a guild together in FPS's like Battlefield and pratice and get everyone on the same page without the effort of typing.
I threw up a server on my computer so that we could all play games together, and mainly because when we have gaming ADD we drop without AIMing the other people to tell them we are jumping ot another game. This way we just have to say something like "Oh, I am playing Company of Heroes now." and we can all jump over and destroy them.