From: "James A. Donald" <[EMAIL PROTECTED]> > Solution is obvious and has been known for a long time > Integrate payment with email. If anyone not on your approved > list wants to send you mail, they have to pay you x, where x is > a trivial sum, say a cent or two. > > Spammers wind up sending huge amounts of mail to unmonitored > mailboxes, which will make spamming unprofitable.
There is also Wei Dai's idea of b-money, I think, which requires every incoming mail to solve a problem about hashes. This could be included in the SMTP protocol, so that the server can generate the challenge dinamically (to prevent replays). This would limit the amount of spam without requiring any "real" money. Mark