I tried to join many other forums but it's very difficult for me to be active since my whole mind is completely focused on Gaming World.
I have managed to stay on the mega64 forums which are cool.
Also I visit the metalgearsolid.org forums, I don't know why. Their community is full of shit and the "veteran" members know that, so they pretty much avoid em. It's pretty fun to troll there though.
When I was very young I was a huge japfag so I was a member of animegarden.com and some other shit like neonsoft.com, yaynetwork.com, darkdominion and (all) their spin offs.
Before that a friend and I ran this whole series of Gundam role playing forums that were pretty e-successful for a long time. Then one day we decided to start a Naruto one, in which a member decided that he wanted to remake it. That got closed down after two years or so, so the surviving community immediately put together this:
http://ninpocho.comWhich is this huge fucking naruto rpg board. They don't know about their secret origins but it is very shit and an embarrassing part of my persona.