THIS! Having run a publicly facing messageboard for many years (no auth, just plain old "write what you want (within reason"), we were able to effectively keep

THIS! Having run a publicly facing messageboard for many years (no auth, just plain old "write what you want (within reason"), we were able to effectively keep the level of spam and abuse off the site with cultural norms within the user base. In one case, we had someone specifically trolling people on the site. We were able to track the poster back to a particular university in Ireland who we notified via their abuse channel (abuse@domain.xxx I think) with a very generic query: "we're seeing someone from your network posting crap like this <link to content>. can you investigate?" The behaviour stopped pretty quickly afterwards... Turns out most network operators want to run a network that benefits all it's users. If you abuse that privilege, they have no qualms with disconnecting you!!