In the end its the ISPs that have the solution in their hands. They could easily detect spamming and stop it - after all, its their bandwidth thats being wasted. Charging 1 Cent for ten messages and waiving all charges below $10 would work well enough I'd imagine. The two hundred and fifteen Spams I just deleted must have come from somewhere. One day soon everyone with an internet account will be getting several hundred a day and even if they manage to direct them to 'dead' letter boxes they will still be gumming up the system.
Most Spam is for products that people wouldn't like to be seen buying in public - Anything for the weekend Sir? non-prescription Viagra, Loan sharking, Porno sites, Penis enlargement, University degrees without studying etc. I'm sure most of these activities are fraudulent scams that could be stopped by backtracking to the advertised service, closing them down and prosecuting the fraudsters. Nothing is done because it isn't seen as a problem by our authorities, but it is a problem - and a growing one. We're already back to using Faxes for important business.
**************************
Through difficulties to the cinema