Spam spam spam spam...

Back in June, aparently, the FTC said that a do-not-email list (like the do-not-call list) would not work, and would generate more spam because spammers would use it as a source of new email addresses.  Though it's a bit late now, I have to wonder about the latter point.  Why not simply map each address into its MD5 checksum before storing it?

So foo@example.com would become "a0b6e8fd2367f5999b6b4e7e1ce9e2d2" which is useless for sending email.  However, spammers could use any of many available tools to check for "hits" on their email lists, so it's still perfectly usable for filtering out email addresses.  Of course it would also tell spammers that they have a 'real' email address on their list, but only if they already had it -- so I don't think that would be giving them much information at all.

I still think the list would be useless because spammers would simply ignore it.  But it wouldn't generate new spam, and it would drive up the cost of spamming by making the threat of legal action a bit more possible.