I imaging the best way to get addresses is to hack or sniff an email
provider. I created a few email accounts from eudoramail.com and received
spam on one of them, and addr I had never used or given out. Since I
created them all at the same time, it was strange only one of them got put
on a list. Every now and then I still check this account, the mailbox is
full of spam. Email itself is an insecure protocol which is why many sites
give you a warning if you request sensitive information by email. Packets
can always be sniffed.

Dan