Using MailWasher, I've been most impressed with the blacklist services provided by ORDB and the like. These services, which maintain lists of SMTP servers left open for spammers to exploit for sending their junk, manage to identify well over 90% of the spam I receive, with very few false positives. I hadn't realized just how effective these tools could be.
However, MailWasher doesn't really work for me. I like to keep my mail program running and checking mail frequently, and having to fiddle with another client-side program is annoying. I went ahead and slapped an ORDB/SpamCop filter on TR's mail server, so that mail sent via open relays can't be delivered to us. We can see in the server logs when messages are bounced, and so far, nothing important has been filtered outjust the pre-processed meat by-products.
So can spam really be fought effectively? Or are we stuck with Nigerian wire fraud schemes involving the deadly cocktail of herbal viagra, human growth hormone, farm animals, and amazingly low mortgage rates?