The spammers started trailing off not long after I wrote the previous post - before hitting their target of 20,000 spam attempts in 24 hours. They punked out at about 18,000 - then I closed the door with the Bad Behavior module.
It was kind of interesting leaving the spammers swarming around my blog as a honeypot, but the load was just getting annoying. Since enabling Bad Behavior, Akismet has had to deal with less than a dozen spammers getting through in about 24 hours - and I haven't had to deal with (or even be aware of) any of them. That's a wee bit of a change...
Bad Behavior makes me a bit nervous though, because it is rather unforgiving by design. If it thinks you're a spammer, or if your IP has been used by a spammer, you're locked out. No second chances. That's good, but it's also a bit authoritarian. There's also no admin interface for it, so if I want to unblock someone, I have to dig around in the database to nuke the appropriate records.
I'll keep an eye on things, but it's pretty cool knowing that this blog could handle a pretty intense load without breaking a sweat, that spammers will not be getting in, and that it takes basically no effort on my part to maintain things. Very cool.