First came to my knowledge thanks to an UNSOLICITED spam email (as opposed to the spam you actually give your email away for sometimes). It was graphic-heavy yet generic in content, boasting the usual too-good-to-be-true discount offer "for only $1". At the bottom, fine print stated that the offer is a 'trial', and that your credit card will automatically be charged full membership fees 2 days later, and every 3 months subsequently. Best of all, it ends with "By providing your payment details in conjunction with the Trial, you agree to this charge." Way to make your scam legal.
Clicked on the site link just for the heck of it, and the dubiousness continued. The site was not much more than a clone of the email (or the other way around) and filled with banners offering vague privileges without any details or T&Cs besides the automatic charges to your credit card.
Only for the greediest and those feeling very lucky.