Sure, it's fun to point out that the best seller at Nabisco is a book advocating a low-carbohydrate diet. But it really isn't fair that I have that chance. You can learn a lot about people by keeping track of what they buy, and that's particularly true of books or videos. Responsible e-commerce sites take pains to assure customers that information about their purchases won't be abused. While online shoppers find this is usually true, those who've never typed their credit card number into a web form are looking for a little more reassurance.
Companies also can remove themselves from the site's directory.
This is aggregate data based on hundreds of people's purchases. We're not calling into question any individual's privacy. When shoppers visit an e-commerce site, they're looking for low prices, wide selection and, most importantly, a sense of security. Seeing a site that plays games with their personal data can only make them wonder what else might be happening to that information. After all, the last thing online shoppers want to see on a store's shelves are themselves.