@doug I think part of it is idealism. In our hearts, we all want to believe that everyone will act as a reasonable person. It's the same impulse that leads Charlie Brown to try to kick the football: "Lucy wouldn't do that again, will she?"

As someone who was on Usenet in the early '90s, yes, she will.

At some point, when your site/service/club/group scales up beyond your immediate circle of friends, you will have to moderate it.