This "pennyblack" silliness fails utterly to address the basic ontological issue: that bits in transit are not being charged by the carriers (if by their own choice, fine, but mostly it's because systems were set up in a socialist scheme to ensure "free transport"...now that the free transport means millions of e-mails are charged nothing, they want the acapitalist system fixed, they hope, with either government laws or silliness about using memory speeds to compute stamp numbers...silliness).
The cost in machine resources to transmit one more e-mail is *really* small. The cost I care about is my time, specifically my time spent leafing through my likely-spam folder checking to see if someone I actually want to hear from sent me something worth seeing. (This is a hassle, because sometimes people e-mail me with questions or comments about papers I've written, and I'd like to see those e-mails. And those e-mails can come from all over the world, can have oddly-worded subject lines, etc.)
If spammers had to pay for the true cost of transferring all their e-mails, spam might slow down a bit, but it wouldn't stop; bandwidth is too cheap. If they had to pay for the true cost of all the time they wasted, spam would be seriously rare. (So would telemarketing calls, and probably even junk mail; those are businesses built on shifting many of the real costs of their marketing effort onto their targets.)
The only way to make spammers pay for the cost of my time is to set up some scheme where your initial e-mail to me costs some amount I set, and then I can let you in after that. But that's a lot harder to set up than hashcash or the memory-bound schemes. And certainly, doing something that takes one second on a reasonably fast machine won't make sending e-mail unusable even for fairly slow machines, while it will make spamming require getting access to lots of other peoples' machines, either by paying them or by taking them over remotely.
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--Tim May
--John Kelsey, [EMAIL PROTECTED] PGP: FA48 3237 9AD5 30AC EEDD BBC8 2A80 6948 4CAA F259
