Where might someone keep them besides a database? By storing passwords elsewhere I mean a non-traditional database.
Allow me to explain. A couple of my friends run high security websites. They needed someone to pentest their website and see if someone could steal passwords. So naturally they asked me if I would do it. I was able to gain access to the server and database, but no passwords or even email addresses. All of the user information was non-existent. I asked them how they did it, but they wouldn't tell me. They didn't use authentication tokens or one time passwords.
What other methods are their to store passwords so that even if a hacker compromises the server it would be extremely difficult for him to get any user information, not even a hashed password?
EDIT: I'm not asking how to hash password, I'm asking what alternatives exist for storing a passwords in a non-traditional database.
EDIT #2: Article was removed because of criticism