It is, surprising, extremely tighly moderated. The have bots as well as hundreds of admins, not to mention the edit-nuts who will do anything to improve wikipedia.
What it does lack is unity. My school uses a single IP, and, it being a school full of teenage boys, there have been many amusing edits to wikipedia. We receive no less than 26
warnings, at least 8 of which were "last warnings" threatening to remove editing access if any further vandalism was committed. Because all the warnings were from different bots and admins, each presumed that we had only been given warnings by them, even though all our warnings were clearly displayed on our talk page. I guess no one bothered to check. And guess what? We're still allowed to edit!