("...I suppose it's just two ways of looking at things, the detraction is that one has a small member base, the plus is that one is dealing with people who are known factors, I just prefer the later, rather than looking over my shoulder each time..." mentioned the goblin)
I'm sort of middle of the road on that one.
I've banned at least a dozen trolls from this board. Sure they supplied post volume and occasionally even said something interesting...but I preferred to keep this board clean and make it a place where people could post without "fear of retribution and flaming".
The extreme would be to keep registration private and limited to known members only.
The other extreme would be something like Trollvalhalla where virtually anything goes short of bestiality, pedophilia, or copyright infringement, and the only reason those things are prohibited is because the site would be shut down if that stuff was posted.