I think that the best place to clean things up is after the threads have been created. Let them veer where they might, though common sense should cause a few volunteers to chime in "hey, let's create a new thread!"

Rather than create moderators, I would prefer that some people be annointed purifiers and post their distilled products in a wiki. To me, there is a difference between a cop and a helper. A cop tells you what not to do, and a helper makes things easier.