Junk email on the other hand has an extremely low cost of transmission in
the current economic model.
There is a difference between the people selling the product, and the people sending the spam. Usually not the same people. The SELLERS do have a transmission cost as they must pay the spammers to spam people for them. Admittedly not much, but the sellers are a much easier target than the spammers. Drive their costs up significantly and you dry up the spam market by implication (for types 1 and 2, which at least for me are the bulk of my 50 or so spams a day).
simon
-- www.simonwoodside.com -- 99% Devil, 1% Angel