That’s it. I cleaned up the comment spam this morning (looking through about 1000 spam comments from the holding bin to find 1 real comment, publishing that, then inadvertently pushing "Publish" rather than "Delete" for the rest. Result: About 1000 spam comments published, which have to be semi-manually excised.
Captchas, here I come.
I hate spammers. As Norwegian boat-owners say: Jeg HATER måker (I HATE seagulls). Seagulls, at least, spread their excrement as a result of doing something useful. Spammers are lower than that.
I HATE spammers. Violently.
Applied Abstractions 
Re. captchas, this looks pretty cool/nice: http://recaptcha.net/
That’s a really good idea, I’ll look into it. Thanks!
Oh, so that’s what happened. I wondered why I found myself manually junking comments.