I downloaded the "Straight Line Persuasion System". I'm currently on the 2nd video. I have to say, it's pretty damn good. I don't really do in-person or over the phone sales, but it's a great background to have when dealing with people trying to sell you stuff. I can also see it being very beneficial when looking to sign up customers for a service and/or gaining investors for a business.
And LOL @ rebill marketers complaining about ethics. STFU and stack paper.