Part of the forum should offer tests. Passing a test allows you access into other forum categories. Surely, people can find a way around the difficulties of the test by cheating and getting in. But it’s just hard enough that passing the test requires about as much intelligence and effort as cheating. You will have places of more intelligent conversation without undermining the fairness of tolerance.
I second this. Actually, I’ve advocated a karma system, so that posting itself is a test that’s graded by the whole community. Ben seemed open to the idea, but he’s waiting on the next version of the phpBB software, since hacks won’t translate from this version to the next.