In any online community where there are rules and some way, official or not, honest or not, for users to help enforce or support those rules, a community will form to do so provided there is reasonable consensus that the rules are actually for the public good. This will often happen even if there is no direct benefit to those who do so (no rewards, no recognition, etc). Likewise, there will usually appear a much smaller group of people who are opposed to rules who will either rules-lawyer or (as the preacher in the following link does) be a nutjob. (To be careful with scope - sometimes particular rules don't make sense, and supporting those rules can be quite a bad thing). There's something nice about seeing spontaneous, relatively-low-ego communities form in support of good things.