penny black

interesting idea out of microsoft (oxymoron?): reduce spam by putting a cpu premium on every mail message that is sent. essentially, shift to a sender pay system, but the onus is not monetary, but paid in computing time, basically using cpu to solve some cryptographic puzzle, which would cost a few seconds for every email. which would be fine for ordinary uses, but would be prohibitive for mass mailings of thousands or millions of spam. of course, this would require the buy-in of everything that sends mail, radically changing the infrastructure. and also of course, who would be happy to supply everyone with a mail client that would do this? hmmm. for a small fee…

on the other hand, would spammers combat this by using things like spyware and viruses to secretly steal cpu cycles from peoples’ machines, making secret distributed spam networks? spamming@home?