Recommender systems already exist in a variety of item domains: entertainment, commerce, news and more. One should expect these systems to become more useful and essential as knowledge volume rapidly grows. The book describes a unique research, demonstrating that the likelihood that users of a social collaborative system would accept recommendations from recommender systems depends on the type of group that made the recommendations and on the users' involvement in the formation of that group. A longitudinal analysis indicates a positive learning curve for experienced users, who acquire a...