I hate spam as much as the next person, so when something is suggested to help combat it, I’m always willing to give it a go.
So in addition to the MT blacklist, and closing off comments after xx days, I’ve implemented Kasia’s idea .

So if someone tries to post without a referrer from my domain you’ll get sent to my error page (stole that idea from her as well – with permission of course).

Thanks

Just a reminder – if you’re going to use it, remember to put in RewriteEngine on so you don’t have to spend an hour or so wondering why the darn thing isn’t working.