I'm not saying this isn't true, but the post is on the blog of a short term loans company who have a vested interest in people believing a short term loan would be preferable to an overdraft fee, and there's no cited report or study that suggests banks make most of their money from fees.
A couple of articles that make me wonder;
http://www.businessinsider.com/chart-of-the-day-how-a-bank-m...
http://www.wsj.com/articles/banks-fee-bonanza-dries-up-14096...