I know I have a couple "real" commenters here who go the anonymous route (but sign their comments). But I'm getting HAMMERED with "anonymous" spam. I know, it takes little effort to delete it but it's discouraging to find eight or ten comments and find all of them being spam. (And apparently Blogger has taken away the capability of having posts older than some date have "closed" comments: that's one thing the spammers try, in the hopes that I don't have moderation, is dropping the comment on a post that's a year old or more).
It's the eternal question, though: Do you put the decent people out to avoid the problems from the jerks? It's kind of like my debating whether to ever do BlackBoard pages for my classes again. (I debate that every semester): there are some people who either use the fact that there are bare-bones notes up as an excuse to skip class, and then come to me all angry when they earn a D, or I get calls from people demanding I put the next notes up on a day when I'm slammed with other work and wasn't going to get to it. But then again - there are some students with learning disabilities who tell me, "Having the notes available after class helps so much" or the dedicated students who print them out (when I have them ready in advance) and bring them to class.
Really, that's one of the questions of modern life, I think: Is it better to put up with/give slightly in to the people who act jerky about stuff, or is it better to go all Severus Snape and not be as accommodating to the decent people?
I don't know the answer to that. Depending on the day I might think the first route was better, or the second.
For now, I'll leave it possible to do anonymous comments, but I really wish the spammers - especially those who write some meaningless non-specific praise and then drop a link for something like pintle-lifting medication at the end of their comment - would have their computers get a massive attack of malware and shut down.