Julie Lerman sees it too:

I got a ton of referral spam yesterday, then left the house at about 2pm. When I came home our power was out and I didn't boot up my computer until this morning.

Outlook has been downloading email for over an hour! It's all referral spam on my blog. Thousands upon thousands. I have never seen anything like it.

I moved my referer list behind a password wall (with the admin pages) awhile back, because keeping the black list up to date was just too much of a chore. I still do it, but if I miss, I'm not embarrassing myself in public.

So anyway, when I took a look at that list yesterday, wow! There were tons of splogs that got created on blogspot. I ended up throwing my hands in the air and putting blogspot on the blacklist. Great Christmas present, that.

Update: Blogging Roller spots the same thing, and he may have the issue pegged:

Apparently, a bunch of morons bought themselves blog spam software for XMAS and spent the holidays setting up blogspot blogs and trying (unsuccessfully, thanks to Roller 2.1-dev) to spam my site via trackback. I took the time to visit each one of the splogs and to set the "objectionable content" flag -- not sure if that'll do much, but it felt good just the same.

My sites haven't seen the trackback thing, but referers, yeah.