I regret to get in anybody's way, but the volume of comment spam I have been getting has been driving me nuts, and Movable Type makes it a royal pain to delete. There is no point in them spamming, I turned off putting links on URLs they include in the spams, but they do it anyway.
Anyway, to stop them, I added a box to the comment form where you have to enter a word I describe. No, I don't put the word in an image -- that popular technique is shutting the blind off from a growing part of the web -- I just describe it in English. Just a warning for those wanting to comment. And hope no spammers decide to automate it (if they do I change the question.)