SPAM COUNTERMEASURES
Several hundred programmers met at MIT yesterday to brainstorm on ways to defeat spam. "William S. Yerazunis, an MIT computer scientist, compared spam to petty street crime - cheap to carry out, profitable for the offender and enormously expensive to halt. 'It's really theft,' said Yerazunis, 46, a researcher at MIT's Mitsubishi Electric Research Laboratories. 'And the theft efficiency ratio is about the same as stealing hubcaps and car radios.'"

Frankly, I don't see the solution as technical but political. There's always going to be some smart hacker who will come up with an end-run around whatever technical solution the good guys come up with. We just have to make the price of spaming so expensive that it won't be worth the risk of engaging in such anti-social behavior.