Email Spam is the 21st century version of Mail Fraud ... that's how they "got" Al Capone ... not on murder, etc, but rather violating laws relating to "misusing" the U.S. Postal System.
15 years or whatever seems fair to me in a maximum security state facility; jail rape, in addition to obviously the jail time, is a powerful deterrent - everyone knows that's what happens in most such state facilities.
Though I'd like to see convicted spammers given an option of getting caned for a large reduction in jail time ... say 1 year deduction per stroke - and then spam the other spammers the canning video; post it on Ogrish.com. But I really digress.
In a nutshell, like many others, I have no sympathy for hardcore spammers - not talking about folks doing a spam run occasionally (by mistake, ignorance, etc), but rather spammers who send tens of millions of spams everyday and engage in all sorts of fraud along the way - via hijacked machines, stolen credit cards, bogus names / ID theft, etc.
Ron