I'd say that about 2-3% of the comments here at BlueNC are abusive or mean-spirited. And that those abusive or mean-spirited comments make up about 30-40% of our anonymous (non-registered user) comments. Based on these very unscientific guesses and the community sentiments expressed in this thread, anonymous commenting at BlueNC is no longer possible.
Does this mean that BlueNC is populated by narrow-minded tools who can't stand to hear what they don't agree with? It might, if registering for a site account weren't automated, free, and easy. The only people excluded by this change are those without the imagination required to think up a pseudonym.