I do quite agree that there isn't any simple solution to the problem of SPAM. I honestly don't even think that there is a techonology available to combat this dilema. Although I do like the idea behind Vipul's Razor, and believe that it will help for to combat some of the SPAM, my inbox receives. I think we as members of the internet society need to convince the major 'FREE' Webmail based services to impose some restrictions on their users.
I've often wondered what would happen if the likes of Yahoo, Hotmail, and Netscape were to require end users to use a valid credit card to receive an account, and charged a nominal fee of $1 per month. To take it a step further, let's say that they also went so far as to limit the amount of email an account can send per month for some probationary period.
I realize that many might say so what, but, one thing about credit cards, is that they have a name and address to trace this stuff back to. In addition if the card number was fradulently used that's a real charge (no pun intended) that can be used to prosecute the perp.
Anyway these are some thoughts I've had, maybe some one can expand on them...