There are a lot of 'flat stomach' and 'whiter teeth' advertising scams proliferating online. The ads lead to testimonials, which lead you to buy the product 'for free' but ask for your credit card. Then your credit card is charged monthly and it is very difficult to cancel the payments.

The best analysis of these scams that we've seen is this excellent article posted today; The Anatomy of a Web Advertising Scam: Investigating the people behind those sketchy flat-stomach ads.