Simply because we seem to see a lot of shitposters as of late, I suggest a few different ideas to help prevent them from even appearing. Don't know if these have been implemented, but at least suggesting them nonetheless.
1) IP Banning. Keep the usual suspension rules and such for good users (i.e. the ones who pass suggestions 2 and/or 3), but if a user continues to make new accounts just to troll and shitpost, ban the IP and its sub-addresses altogether. Drew Pickles, the (in)famous KYM troll from a few years back, kept switching accounts over and over, and Rip Cheato seems to be doing that this time around. Would probably make things simpler if we were able to mass-block anyone who attempts to maliciously mess with content on here.
2) A probationary period for new accounts. I'd say a good week or so. In this probationary period, they aren't able to create new articles or post on articles/user pages, but can post in the forums. And when they do post, the mods can be aware and hand out the ban if it appears malicious and blanket-delete the posts. This would prevent them from showing up and shitposting somewhere "important" immediately.
3) A legitimate semi-visible (on userpages and inthe forums, but not on articles) karma system. Upvotes and downvotes being separate from this system, since everyone at some point will post something well-received and something poorly-received. In this, users can give positive karma for legitimate help and insightful posts, both in the forums and in the main articles, but receive negative karma for trolling and shitposting. It would have to be mod-watched, so as to prevent mass karma-awards just because "I approve of this post," but if properly implemented and watched, it would quickly separate good users from bad ones, and could help legitimate new members fin the right users to listen to and learn from.
Like I said, I don't know if any of these are implemented, and part of me is sure the ideas have already been thrown out there. But I'm (re)submitting them anyway, because we've had a slew of regular trolls lately, and I would prefer to prevent that, fun as it may sometimes be to mess with them.