Working at Davis-Kidd allowed me to see how prevalent and disgusting the self-help industry. There is a cure-what-ails-you, fix-what-your-parents-broke book for everything you can imagine. Some of the problems with this industry, as I see them, are that they all blame somebody else for everything, there are very few that tell the reader to take responsibility or maybe even "just deal with it" and they try to give you immediate fixes for things that should take a long time. You shouldn't be able to get out of debt tomorrow or overcome procrastination in 8 days or whatever they proclaim. None ever talk about patience or diligence.
Some of them are huge sellers; you name a diet book, the Purpose Driven Life, and Rich Dad, Poor Dad. Some of them will surely help people but I think a vast majority of the people will get nothing more than excuses and bad habits.
Here is a link to a Motley Fool article about the fallacy of Rich Dad, Poor Dad.