Well, I'm sad. I had to turn on the "Moderate Comments" button - seems I'm a spam target. Not new posts, but quite a few of my older posts have icky sex link comments attached to them now. So, for a while at least, I'm going to have to moderate all comments. If it only keeps happening to the older posts I'll change the moderation to any post older than 14 days.
Sorry about this - I guess it was bound to happen eventually.