Blizzard.
Member count of his forum: YOU
Active members: Imma let you Finnish
Posts per day right now:Over 9000
:3
Honestly though, it's not like RPG Maker a new concept either :p Successful forums are the conjunction of innovative/interesting ideas, active user bases and regular, consistently high quality new content. If you think your forum has that, then it should succeed, but RPG, again, is old now and the forums established already such as CP are already taking in the new market of users.