Here is a thing at Making Light. There are probably other relevant posts on said blog, but this one seems to have what I consider the key points.

I'll quote some specific points that might be more surprising:

\5. Over-specific rules are an invitation to people who get off on gaming the system.

\9. If you judge that a post is offensive, upsetting, or just plain unpleasant, it’s important to get rid of it, or at least make it hard to read. Do it as quickly as possible. There’s no more useless advice than to tell people to just ignore such things. We can’t. We automatically read what falls under our eyes.

\10. Another important rule: You can let one jeering, unpleasant jerk hang around for a while, but the minute you get two or more of them egging each other on, they both have to go, and all their recent messages with them. There are others like them prowling the net, looking for just that kind of situation. More of them will turn up, and they’ll encourage each other to behave more and more outrageously. Kill them quickly and have no regrets.