Recommender systems can be made more useful as marketing systems in other ways as well. Current recommender systems are mainly “buy-side” systems; that is, they are designed to work on behalf of the consumer to help him decide what products he should purchase. However, modern marketing is designed not only to maximize utility to the customer but also to maximize value to the business at the same time. The recommender system could produce an indication of the price sensitivity of the customer for a given product. For instance, one customer might be willing to purchase the product at a price that would earn the site ten cents of profit