An interesting lecture on password psychology.

Lorrie Faith Cranor: What’s wrong with your pa$$w0rd? | Talk Video | TED.com

Lorrie Faith Cranor studied thousands of real passwords to figure out the surprising, very common mistakes that users -- and secured sites -- make to compromise security. And how, you may ask, did she study thousands of real passwords without compromising the security of any users? That's a story in itself. It's secret data worth knowing, especially if your password is 123456 ...