The majority of them are scams. They pop up faster than the FTC can go after them. They don't care if you get sued and they do little, or nothing, to try to prevent that from happening
Read in the following link to the FTC, "Facts for Consumers".
Knee Deep in Debt
I'm pretty sure you will see countless hits on the subject if you did a Google search with the same term as your thread title
eta
Alfred gives an excellent first hand account of his experience, that many people go through with the majority of those types of companies. Alfred was very, very lucky he didn't have to include being sued.