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.
"In fact, roughly half of respondents to the ICBA survey say that overdraft fees constitute their most profitable non-depository and non-lending product, despite regulatory changes that have crimped their income potential."
So basically the article is completely wrong when it says:
> The most profitable source of income for banks is not mortgages, credit card fees or mutual funds, but the fees they charge clients for these short-term loans.
http://independentbanker.org/2014/01/finding-more-fee-income...