the problem is who qualifies as a gang. sure, a gang could have 50 members, but how many people are active?
also it sets up an eleteist scenerio:
"oh, you haven't posted enough in the forum, you cant be in a gang"/"your gang is full of newbies, your not worth acknowledging"
if it was done fairly, this is a great idea. maybe a small (teeny tiny) webpage for each gang?