Among the many important points that the different blogs brought up, I found the best to be "using an alias vs. a real identity online" and "Are you contributing to the discussion?". In using an alias, commenters aren't afraid of others being angry with them for posting vulgar remarks on their blogs. Using a real identity, however, can have consequences.
When asking oneself whether or not they're contributing to the conversation, it can create a much better code of conduct for all commenters to follow.