I have never seen anyone attempt mediation. I was thinking about that earlier today. My feeling is that if there was no moderation, that some people might start trying to mediate. Maybe if they had enough status, they might get somewhere.
The problem is that you can’t mediate if you have power. Mediators must exert power through persuasion. Most people don’t have the patience and tolerance for that, and in the end, they resort to moderation. If you do that, no one will have any trust in you, and there’s no point.
My guess is that most sites use moderation because that’s the only thing they can control. If people won’t behave in an acceptable way, they will be deleted.
What you do depends on what the owners of the site want. I think most owners want people to be nice—although what nice is, is kind of hard to define. Some people have much thinner skins than others.
But I don’t know of any sites that use mediation. They must be out there. Any examples?