Anil Dash wrote a list of ten internet rules, which all make pretty good sense. Here's one that is pretty well known to bloggers. Or should be.
If your website's full of assholes, it's your fault.
That's the rationale behind Neatorama's comment system. We have few rules, but if a commenter breaks them, they are edited/warned/deleted/banned depending on the behavior. That's to make it nice for everyone else, because we LOVE it when people comment to add information, make jokes, tell personal stories, or just give feedback on a post.
People will move mountains to earn a gold star by their name on the Internet.
Well, we don't have gold stars, but we do have ♥s for comments (which anyone can hand out) and the "comment of the week" (which doesn't happen every week, sorry). Besides, if you are a registered Neatoramanaut who has not been edited, chastised, moderated, or banned, you are part of an elite group of wonderful people, so pat yourself on the back. Here's a rule that made me smile:
Given enough time, any object which can generate musical notes will be used to play the Super Mario Brothers theme on YouTube.
Ha! Don't we know that! Read the rest of the rules, with related links, at Dash's website. Link -via Metafilter
But I'm not sure if I agree with the assholes being a the site admin's fault, depending on the nature of the site. For more sites where discussions are targeted, narrow, or kind of have some external guidance (e.g. responses to random news), it can be kind of easier to just kick out anyone that doesn't behave. For more open ended sites, where it is based more on a developed social community that can end up talking about a lot of off-topic things, it gets muddier. You can have people that are perfectly reasonable about 95% of topics, while having something they get more jerkish, or worse over. Then you have issues of deciding to either restrict topics due to random issues of members or get rid of members that probably are making a net positive contribution. My previous foray into site administration fell under the latter category, and the amount of cat herding needed and potential for drama made me decide to never do that again and I would probably in the future only manage a site where with a narrow topic with the option for stricter, semi-arbitrary rules to keep people away from problem topics.