EN: O'Reilly Radar has a interesting discussion about the technologies to fight e-mail SPAM. But I am not sure if fighting SPAM alone makes the world a better place. SPAM is a symptom that shows that (1) there are too many unsecured computers connected to the net and (2) there is enough criminal energy out there that makes use of them. If the SPAM problem is solved somehow (some proposals are mentioned in the article) both points aren't solved. It might lead to an increase of other computer crimes like blackmailing companies with DDOS attacks using botnets. Crime is partly the result of missing options of legal work for the people committing the crimes, but well ... that's hard to solve. Increasing general security of computers is easier. Unfortunately the focus in most companies/communities seems to be on implementing as much features as possible while increasing complexity and reducing security.
Using an unsecured machine in the net is like driving drunk ... you don't endager only yourself but also others. My personal solution is using OpenBSD (but sure there are others ;)).