In general, the customers of these companies have no idea that they’re customers until they discover mysterious charges on their credit-card bills. When they investigate further, they find that during the checkout process at reputable websites like priceline.com or 1800flowers.com, they inadvertently clicked on a link which automatically gave their credit card details to these rip-off merchants.By the way: CPM means cost per thousand, or how much these companies pay the website per thousand clicks on the ad (I learned this in the comments). Previously those same companies harassed another blogger in court about this same thing. Definitely a good reason to keep your an eye on your credit card bill.
Via Kevin Drum.