I thought I had a vague idea of what goes on out there, but this one doesn't make much sense to me.
UPDATE: Well, I think I've partially solved it. I should have known -- my My Blog Log stats helpfully indicate that the "next blog" button is the most frequently clicked link today. Apparently something's just whipping through the blogs one after another. That would be why they're all Blogger addresses... Still, I'm not sure what it gets anyone.