Gates: Buy stamps to send e-mail

CNN are reporting that MS founder Bill Gates is suggesting we buy "stamps" to send e-mail (paid in cpu cycles that we rent to others). After all here in snail mail land I'm sure we'd have alot more spam is mail is free to send.
Could this be the very end of the "free internet"?
Although the point is valid I believe this would do nothing more then put a small dent in the junk mail setup on the net, I have two junk mail accounts, these are e-mail accounts which I used to use but had to drop them as they were getting hammered with junk e-mail (100+ a day) so I changed my address so it looks like a anti-spam messure but is actually a valid address, I've also setup spam filters blocking whole countries, now I get about 2 junk e-mails a day. :-)