I run my own forums (not on this topic, which is why I'm here), and I have a potential tip for this place.
We created a forum on mine, analogous to STS here, with one additional feature. It auto-deletes threads after a period of no new posts on them. While any normal moderation is subject to consensus of the mods, for this, we let them move any post or whole topic to the water-cooler thread and leave a note behind if they choose.
There are "no holds barred" on the water-cooler forum. Lets people talk trash, blow off steam, and so on, and they all auto-magically disappear after awhile when people lose interest. This makes it far easier to get people to accept much more restrictive rules elsewhere...and if something good develops over there, a mod can just make it sticky. Trolls get tired of getting shoved off good threads and give up - or after consensus, we boot them and the IP range they rode in on, along with their entire posting history.
I probably have fewer issues on mine due to our quite restrictive entry barriers, which are basically I have to like you already, and know who you are, and you have to ask - to prove you're a human and not a troll. This works on my site with is mostly for scientists but isn't as workable for places like this.
However, I've also got a forum for general trading and philosphy that isn't getting hit by many other than myself, which isn't how I like things. Any traders here who want to talk trash over there (well, hopefully it's not trash) are invited. I need a name and an email to set you up, you can pm me from here if you want in over there.
We like real names, which might hinder some, but since we don't talk about things other than trading philosophy, it might not be as important to retain anonymity there as it might be other places. FWIW, here's a link to that part of my own world.
http://www.coultersmithing.com/forums/viewforum.php?f=51