The software is pretty neat - especially if you use a hotmail, yahoo or gmail account (with which it integrates very easily). Worth giving it a go - I'd send you a link to more information, except most of their site is down from all the traffic they've received lately (DDOS or not).
What's interesting is that I think even I was hit by this. I typically receive 10-15 spams a day at my normal Gmail account, but yesterday evening I got home and found that I'd received almost 100 spams in the last 12 hours. What was weirder than that was that about half of that got through Gmail's spam filter, which rarely happens.