NextStar is a cloud based service where users can view and rate the work of lesser known artists. Artists may include actors, singers, screenwriters, comedians, painters, sculptors and filmmakers. Based on user ratings, the application recommends new content and/or artists to each user. With reference to NextStar, compare and contrast how the K-nearest neighbour (k-NN) algorithm and matrix factorisation might be used to generate content and/or artist recommendations.