Several months ago I signed up for a free trial account with a popular online shipping service. Signing up was easy. Until I was asked for my credit card information. Naturally I hesitated. Why did this company need that information for a free trial? I knew this trick. I'd sign up, use the service a few times and promptly forget all about it. But the company had my credit card information, and that free trial would automatically turn into a subscription unless I cancelled it. And I probably wouldn't even notice. At least not until several months later when I would recognize the recurring charge on my credit card bill.