With more and more people getting annoyed at spam, and realizing that for some reason I don’t have a problem with it, they ask me what I do about it. I’m using three tools to fight spam:
Get an email address at www.despammed.com. This is a good address to give in cases where you’re afraid it might be seen by spammers, e.g. on web pages, in forums, in usenet news or on mailing lists. The guys at despammed have some good spam detection tools and very little spam gets through there. Don’t use this address in day-to-day conversations with friends, though, because mail going through there takes quite some time to get to you.
I collect all my mail accounts on a central server (eressea.upb.de) using fetchmail, and run it through procmail. That way, I can run mail through special filters like Spam Assassin, a very clever program that gives your mail a spam score, depending on how many spam-typical things it finds in the text. You can decide what to do with mails that score more than a certain number of points, either mark the subject so it says ***SPAM***, or simply throw it away for good.
ASK – Active Spam Killer
ASK checks all senders against a whitelist of people that are allowed to send mail to you. If somebody is not on that list, they get a message asking them to please reply to that message, and if they do, ASK will put them on the whitelist, and the original mail gets passed on to you. That way, each new sender needs to register with your ASK protection once. Most spam doesn’t have valid return addresses, and never gets authenticated. And if someone does, there’s also a blacklist to block him from ever sending you anything again.
Those tools together, when used correctly, can eliminate almost all your spam, without losing important mail. You need to have a Unix account somewhere, of course. I don’t know of any good software that would do the same thing on Windows and not cost a lot of money.