Originally Posted by skalogre
Post count is always a sketchy tool to use to enforce a site standard. I don't see it being such a bad thing in this case, but for things like posting links, using signatures, etc, it will often just encourage new users to post junk one-line posts in order to reach the needed mark.
If a forum is quite controversial or troll-attracting, one good way to limit posting access is to charge a minor fee, say $2, to gain permanent access to it. Most people won't spend good money to be a jerk, plus you get their real ID when you charge a payment.