Shit, I really don't remember the forum that preceded GamingW back when I was like 12, but it was some sort of setup where literally every video game ever made had its own board where people could post cheats and unknown facts about the game. It was a really active place and I was actually the mod of the Silent Hill discussion forum and was in the running to mod FFVII, which was like the most popular place there.
Other than that I haven't really been a member of any forum other than GW. I had a pretty successful
Myspace blog (if anything on Myspace can be considered to be successful) in which I spread anti-Christian propaganda on an almost daily basis. It was a pretty funny experience, but now its decommissioned. Once my blog got popular other people stopped reading what I had to say and started trying to use my area as free advertising for their shit.