Some sites have a way where users can post in a thread without bumping it. This theoretically prevents really dumb threads from continually rising to the top just because they're so dumb that people can't resist popping in to call the TS an idiot, which I've noticed is a bit of a problem here on sherdog. In theory, it will allow posters to do some of the mod's work for them by preventing them from having to do so much cleanup work, although this depends somewhat on whether or not posters are aware of the function and have the inclination to use it. It almost has to help at the very least a little bit, though.
For example, the popular imageboard "4chan" has this thing where you can type "sage" in the email field of a post and that prevents your post from bumping the thread to the top. I'd imagine it could be done easier here, with a check box or something.
Here is the encyclopedia dramatica entry on "
sage." Not exactly the most serious reference tool but it's all I have found on the subject.
This could easily eliminate a lot of trolling. Trolling depends on outraged posters taking the bait and continually bumping the thread. People aren't going to stop taking the troll bait, but they very well might remember to hit the "do not bump" button in the process.
You might also consider making it so you can't bump your own thread, but people might really hate that.