Like many, I use the Amazon Associates affiliate marketing program when linking to books and some other products from my websites. It's a simple referal service. Users can create links and when readers on their websites follow those links and make purchases, Amazon pays a referral fee.

There are lots of ways to use the Associates service, but I mostly use it in the links to my own books (e.g., at right). Because of the economics of the book business, purchases via an Amazon Associates click can add a considerable percentage to the royalties authors earn from the sale of the book alone.

One of the side-effects of this practice is that Amazon Associates Reports offers a rare chance to see some of the other things one's readers are also purchasing. You see, when a user follows an Associates link, Amazon awards a referral fee for anything they buy during that session. Which means those items also show up in your reports. Some days, such reports are more interesting than others.

Consider the following excerpt from one such report. In addition to some purchases of Persuasive Games and Unit Operations (thank you very much), we can learn a bit more about my readers. For example, in addition to videogames, they are interested in environmental issues, detective fiction, and leadership. Also, diaipering bottoms... and doing other things to them.

There is nothing personally identifying about such information, so one can't really connect website visitors to their Amazon purchases. Nor is this information public in the way that the much-maligned Facebook Beacon system. But certainly these less visible aspects of privacy as it relates to online purchases deserve more exploration. It still might be possible to triangulate a guess from blog comments, server referral and outbound link logs, and Associates reports. Ironically, the less traffic an Amazon Associates-enabled website, the more certainty one might be able to have in guessing what products a particular visitor had purchased.

On a more mundane note, given enough data Amazon Associates offers an interesting opportunity for authors (from books to blogs) to learn more about the other media their readers enjoy. I'm not sure such knowledge would inspire direct changes to the way I write, but over time patterns might emerge that I'd want to pay attention to. How else would I know that my readers are so frisky!