Unfortunately, despite all the technical measures and social pressure we can deploy, the only real long-term solution to this problem seems to be a law. Yes, they are the solution of last resort (at least for everybody but nanny-state liberals), but all other solutions yet devised have failed miserably, like a band-aid on a sucking chest wound. (Recall that not having to see it does not mean not having to pay for it.) However, a very similar problem was solved nearly overnight, with no infringement of anybody's rights, nor any government expense, by a simple law.
That was the "junk fax" problem. Unscrupulous salespeople were faxing ads to any fax numbers they could get hold of. They tied up your line, used up your paper and toner, and made you wade through their ads to get to your legitimate faxes. Spammers tie up your ISP's lines and yours, use up your ISP's disk space (and yours if you store your email on your own machine), and make you wade through mountains of garbage to get to your legitimate email. (Amusingly enough, the "King of Spam", Sanford "Spamford" Wallace of CyberPromotions, was also one of the big figures in the junk fax business.)
This was solved by a simple law that said, in essence, that if someone sent you an unsolicited commercial fax, and you didn't already have a voluntary business relationship with them, you could take them to small claims court, and walk away with $500 of their money, or actual damages if greater. No need for Big Brother to snoop on your faxes. No need to whine to the police and hope they get around to doing something about it. (No insult intended to the police; they've just got much more important crimes to deal with!) No need for the hassle and expense of a criminal case or a larger lawsuit. No interference with legitimate faxes. No new bureaucracy.
In 1997, Representative Christopher Smith proposed a small modification to the "no junk faxes" law, that would just explictly add email to that law. Currently, it is theorized by some that the current law covers email as well, at least if your computer has a printer attached, since it would then meet the legal definition of a "fax machine". However, this approach has never been tested in court, and my own opinion is that it would be laughed out of court. (Disclaimer: I am not a lawyer, and even if I were, the above should still not be taken as legal advice.)
Some commonly asked questions:
There have been a few additional federal laws proposed, mainly by Senator Frank Murkowski of Alaska (send him comments at commercialemail@murkowski.senate.gov, and Representative Torricelli, of I forget where. However, these both interfere greatly with the way ISPs conduct both business and technical operations, do nothing about the cost of the transmission of spam, and contain numerous other flaws. There are also laws against spamming in a few states (most notably Washington (state, not DC)), and other countries (most notably Germany, in whose case system-attacks are considered legitimate self-defense).
Next: Who knows? This is the end of this series.