I hate studies like this. Do people pick common passwords, of course they do. Does everyone pick an easy to guess password, of course not. Can it be blindly determined, for any given user, if their password is "simple" or "complex"? No.
The article puts the blame on the end user, when the truth is the problem is with the websites storing the passwords in plain text or as un-salted hashes and not locking out brute force attacks. What the researchers are really arguing is that
1) your account may be compromised if hackers break into the website and steal all the passwords.
2) your password might be easier to guess if it is related to you, hackers are targeting you personally (not likely), and the website doesn't lock the account out.
Don't blame the user, blame the developers and administrators for being lazy and/or inept and failing to protect people from themselves.