Recommender systems systems apply data analysis techniques to the problem of helping users find the items they
would like to purchase at E-Commerce sites by producing a predicted likeliness score or a list of top–N recommended
items for a given user. Item recommendations can be made using different methods. Recommendations can be based
on demographics of the users, overall top selling items, or past buying habit of users as a predictor of future items.
Collaborative Filtering (CF) [19, 27] is the most successful recommendation technique to date. The basic idea of
CF-based algorithms is to provide item recommendations or predictions based on the opinions of other like-minded
users. The opinions of users can be obtained explicitly from the users or by using some implicit measures.