Score! The first results from The Product Recommender Engine arrived.
A group of customers received a business-as-usual email of product highlights. Some of these customers returned and bought some more stuff. Let's call that conversion rate index 100.
Another group received customized emails, recommending specific products, based on the product purchase history as decided by The Engine. These customers converted at a rate of index 157. Money was made.
Innohead is now in the process of packaging the recommender algorithm as a standard component on the platform. I wonder who else, besides booksellers, could use the system?