Greylisting -- bad

At Marco.org there's a short article discussing why greylisting is a bad thing.

I've always thought it wasn't much more than a stopgap. Marco says that his beef is the fact that email is no longer instantaneous because of the delays that SMTP graylisting injects. I agree that's important, but it's not that important to Me since I never send anything urgent in email (I'm aware of graylisting and delays) and I let my mail sit and ferment a few hours, usually, before reading it. Immediacy is important to other people, but it's not a big deal with me.

The reason it's a stopgap is that eventually botnet spammer software and viruses will be modified to retry. When that happens, we'll be back where we started, with spam classifiers.

Likely, then, there'll be some new mode of speeding things up, perhaps by putting fast but not so good classifiers in the front of the queue, passing through anything that clearly isn't spam, and passing the possibles to the heavyweight classifiers like spamassassin (which I can't stand because it's so heavy, I use bogofilter instead, it's simple and I don't mind training it from the command line, but that really doesn't scale and there should be an easy way to train so that non-geeks can use it without trembling).