From the tutorial published by Martin Ester in RecSys 2013
Future Research Directions
--Recommendation in heterogeneous networks with more than 2 entity types
--How to recommend entities of one type to entities of another type?
--Explanation of social recommendations
--A. Papadimitriou, P. Symeonidis, Y. Manolopoulos: A generalized taxonomy of explanations styles for traditional and social recommender systems, Data Mining and Knowledge Discovery, 24(3), 555- 583, 2012.
--A. Sharma, D. Cosley: Do social explanations work? Studying and modeling the effects of social explanations in recommender systems, WWW 2013
--How to preserve privacy when employing social networks?
--Recommendation in mobile social networks
--Can we develop distributed algorithms?
-- How to exploit the user location?
--Recommendation in social networks with user-generated content
--How can we integrate topic models?
