How can I track if my mailing list I use for my fortnightly newsletter has been stolen?
One way to detect if your mailing list has been stolen is to use Honeytokens.
Create a new mail id at say, gmail or yahoo. Add that email id to your mailing list. But do not give out that id for anything else. The only emails that id is supposed to receive are your newsletters. If you get any other mail, that’s most likely because your mailing list database has been stolen.
To reduce the chance of spammers accidentally guessing the id, use a really obscure, long email id. And, again, remember not to use it for anything else!
For more ideas, check out Lance Spitzner’s excellent introduction to Honeytokens in Securityfocus.