Recommender systems are similar to, but also different from, marketing systems and supply-chain decision-support systems. Marketing systems support the marketer in making decisions about how to market products to consumers, usually by grouping the consumers according to marketing segments and grouping the products in categories that can be aligned with the marketing segments. Marketing campaigns can then be run to encourage consumers in different segments to purchase products from categories selected by the marketer. By contrast, recommender systems directly interact with consumers, helping them find products they will like to purchase. Supply-chain decision-support systems help marketers make decisions about how many products to manufacture, and to which warehouses or retail stores to ship the products. These decision support systems use analytic technology to predict how many of which products will be purchased in each location, so the right products are available for consumers to purchase. Many supply-chain decision-support systems answer questions about aggregates: of all the consumers in Minneapolis, how many will buy toothpaste in February? Recommender systems answer questions about individual consumers: which product will this consumer prefer to buy right now?