Sage: recommender engine as a cloud service.

Project Sage is Microsoft's all-purpose recommender system, designed and deployed as an ultra-high scale cloud service. Sage focuses on both state of the art research and high scale robust implementation. In the research front, we demonstrate new pre-processing and cleaning techniques, a novel probabilistic matrix factorization model for implicit one-class data, and a relatively new evaluation framework. In the engineering front, we present a working service deployed on the Microsoft Azure cloud, which provides easy-to-use interfaces to integrate a recommendation service into any website.