I'm getting a series of comments that are like classic comment spam—a vague phrase, out of context, stuck seemingly at random on old posts (e.g. “charity begins at home”). Usually these are just a cover to link to some site that is trying to raise its googlerank. What's odd about these is that all the “author” links are to pages of the form nohomepage.domain.com where “domain” is a domain that is not registered. So those links don't work.
The comments also have a 'hidden' link to a second domain (usually the period is hyperlinked). But those domains don't resolve either.
So I think I'll prune them. But I admit that I can't see the point of this sort of spam except (1) to bury existing comments or, maybe, (2) to lull bloggers into a false sense of security when they check the domains and find they don't work…and then activate something in them next week (or sell them) with an increased googlerank.
UPDATE (6/15): Adding
to my MT-Blacklist blocking list seems to do the trick…