I've decided to block anonymous comments.
Now, I realize we get a number of very welcome anonymous comments, usually signed in the text. Got one this morning, as a matter of fact. I'd ask all of them to take a moment to sign up for a Google account. It's easy and doesn't cost a cent. There's a link on each comment page.
I regret inconveniencing these readers, but there's another sort of anonymous commenter who's not so welcome. I'm afraid that sort also doesn't realize that, through Site Meter, they can be traced anyway.