Comments:

Opt-out mechanisms are useless in combatting SPAM, as anyone who deals with it knows that merely opening a message can add his address to more mailing lists, not to mention that many "opt-out" links are fraudulent to start with. Any regulation that does not enforce an explicit "opt-in" requirement for receiving commercial email will have no effect on SPAM, period. Financial disincentives are the only solution, both for the companies whose products are advertised and for the actual senders. The first would hold the advertiser responsible and prevent hiding behind pseudonyms and off-shore mail relays; the second would attach a price tag to outgoing email beyond some reasonable number. With the time, effort, and money already spent on anti-spam measures, I, for one, would be glad to pay a nominal amount for outgoing mail.