What is Recommender Systems?

    Have you ever been to websites like Amazon, Netflix, or Pandora Radio? If so, you must have known the Recommender Systems, or at least you've used it unawarely.

    So, what is Recommender Systems(RSs) exactly about? The picture below is an example for you.

    As you can see, this is a cropped picture from my Amazon home page. it shows me the item that I've viewed before, and then, it recommends me several items which are viewed by customers who also viewed the same product as I viewed. 

According to Francesco Ricci, the author of Recommender Systems Handbook, RSs are software tools and techniques providing suggestions for items to be of use to a user.The suggestions relate to various decision-making processes, such as what items to buy, what music to listen to, or what online news to read.

    So, why does Amazon do this? Why do they spend money to build a system to recommend you something else?

    A simplest answer would be that they want to make money. They want to maximize the possibility that you'll see what you like on their websites, and click the "add to cart" button. Because most of the time, these kind of websites would have a great number of products, sometimes, customers would feel lost because there are too many categories, items, choices that they don't know how to find what they want. RSs is a way to simplify the choices for customers, bringing the suggestions that would be needed by the customers.   

    It's obvious that more and more e-commerce companies are inclined to use RSs to help their business. And in the next topics, we are going to talk about stuffs like how RSs impact businesses and exploring the techniques that used by RSs.