1. There can be no ongoing discourse without some degree of moderation, if only to kill off the hardcore trolls. It takes rather more moderation than that to create a complex, nuanced, civil discourse. If you want that to happen, you have to give of yourself. Providing the space but not tending the conversation is like expecting that your front yard will automatically turn itself into a garden.Link
2. Once you have a well-established online conversation space, with enough regulars to explain the local mores to newcomers, they’ll do a lot of the policing themselves.
3. You own the space. You host the conversation. You don’t own the community. Respect their needs. For instance, if you’re going away for a while, don’t shut down your comment area. Give them an open thread to play with, so they’ll still be there when you get back.
4. Message persistence rewards people who write good comments.
5. Over-specific rules are an invitation to people who get off on gaming the system.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.