The vanishing civility: The game of jerks, bozos and assholes
When I was the editor of Dr. Dobb's, we were very concerned about how to create a lively discussion forum that was free from jerks and unpleasant people. Ultimately, we settled on two components: treat everyone respectfully even those who seemed to be trolling, and delete all insulting posts. This largely worked. Similar elements seem to work here on HN too. That the efficacy of this approach is repeatable suggests that the problem exists primarily b/c sites are willing to put up with bad behavior.