One of my blogs just got hit by this yesterday, and I’ve seen discussions on how to deal with this, technically, in various developer lists. Do a search for “blog spam” on Google, and you’ll find plenty of discussion about it.
Here’s one particularly extensive thread:
There’s already a blacklist tool: MT-Blacklist
Everything old is new again?
Just what we needed. Another wholesale attack on an Internet service – it seems like the entire structure of IP based communication is now under attack… my email inbox is flooded, my IM clients have lost much of their functionality (over the past few months 95% of the “people” who’ve added me to their lists, via ICQ, have been spammers), my email lists all need to have new members moderated to prevent spam, and now I’m going to have to fight off attempts by these bastards to flood my weblogs. Great.