One would have to live on the dark side of the moon in order to not observe—each and every day—the results of the techniques that we are about to discuss in this chapter. If you visit www.amazon.in, watch movies on www.netflix.com, or visit any retail website, you will be exposed to terms such as related products, because you watched…, customers who bought x also bought y, or recommended for you, at every twist and turn. With large volumes of historical real-time or near real-time information, retailers utilize the algorithms discussed here to attempt to increase both your volume and the amount of purchases.

The techniques to do this can be broken down into two categories: association rules and recommendation...