Is not trivial- the cost of spam is enormous
"...About 95 per cent of emails this year - up from 70 per cent in 2006 - were classified as junk messages, according to a report from US security firm Barracuda, Agence France Presse reported.
Most of this is deleted by email filters run by Internet providers before it hits inboxes..."
I believe the punishment should fit the crime- thus all spammers are to be reduced to- Spam!
Put through an industrial-grade mincer, rendered down, seasoned and sold for dog tucker. (which is all Spam is fit for!)
If it won't sell as dog tucker, at least they won't take up much cell space!