Amazon seems to really understand me. Or, at least, my reading preferences. Running, garlic, data. Yup, that pretty much sums me up.
Although accuracy metrics have greatly helped the field of recommender systems, the recommendations that are most accurate are sometimes not the ones that are most useful to users, for example, users might prefer to be recommended with items that are unfamiliar with them, rather than the old favorites they do not likely want again.A Survey of Collaborative Filtering Techniques