How do recommendation systems work?

Question

I\'ve always been curious as to how these systems work. For example, how do netflix or Amazon determine what recommendations to make based on past purchases and/or ratings?

Answer 1

This is a classification problem - that is, the classification of users into groups of users who are likely to be interested in certain items.

Once classified into such a group, it is easy to examine the purchases/likes of other users in that group and recommend them.

Therefore, Bayesian Classification and neural networks (multilayer perceptrons, radial basis functions, support vector machines) are worth reading up on.