As a security professional I strongly believe passwords is the single most important topic which is far more subtle than most folks realise.  Understanding the basics is vital and yet most people don’t.  I think one of the best ways to gain an appreciation of the subtleties is to discover how easy it can be to compromise a password.

Here are some links for those how want to get their head around the technicalities.

Good introductory article (Ars Technica keep coming up with good current articles on passwords)

There is of course a conference dedicated to password cracking

This has connections with the Password Hashing Competition (PHC) which is trying to improve things

and last but not least, probably the most powerful password cracking software freely available