I’m at almost a quarter of a million spam messages (249,744 to be precise, by the time I post this it should be more than 250 thousand) caught by Akismet so far. I turned Akismet on in January of this year. That’s more than 50,000 spam messages a month. According to the Akismet site 92% of the comments it sees are spam.
The problem is very unevenly distributed however. I have a few other blogs out there, and they tend to get more like a few hundred spam messages a month. I just wanted to point that out given the degree of blowup I see when things happen like someone has to turn off comments for a while. The spam problem is not uniformly distributed, just because you get a managable ammount of spam comments that doesn’t mean someone who blogs about just about the same stuff isn’t getting hundreds of times more.