Hey Wayne, couldn't you have the posts expire in the DMZ, like the polls? I mean, yeah, they ARE fun to read, but if they get to big, I'm sure they cause server problems.
After all, the DMZ is just that, the DMZ. There's nothing really there that is of a viable argument to store for an extended period of time. Originally, I had thought that you could just have them expire, after not being read for some time, but after someone figure's out the limit, it wouldn't take much for them to 'bump' it and make it's time reset.
Then again, I know next to NOTHING about the server software you're using. You could also make the DMZ a place for individuals that have exceeded a number of posts. That wouldn't stop the quagmire of post count raising, but it may help.
I'd rather not lose it all together, however. Some of my best laughs have come from that forum. :-?