One-Class Collaborative Filtering

Many applications of Collaborative Filtering (CF), such as news item recommendation and bookmark recommendation, are most naturally thought of as One-Class Collaborative Filtering (OCCF) problems. In these problems, the training data usually consist simply of binary data reflecting a user's action or inaction, such as page visitation in the case of news item recommendation or webpage bookmarking in the bookmarking scenario. Usually this kind of data are extremely sparse (a small fraction are positive examples), therefore ambiguity arises in the interpretation of the non-positive examples.