What can we do?

 
Damn Spam: The losing war on junk e-mail.

"More than a hundred billion unwanted messages clog computer networks every day." ... "Spammers usually need to send a million e-mails to get fifteen positive responses; for the average direct-mail campaign, the response rate is three thousand per million."

Can you imagine the cost savings if there were any way to stop these theives from stealing bandwidth?