Pablo Castells, Jun Wang, Rubén Lara, Dell Zhang: Proceedings of the Workshop on Novelty and Diversity in Recommender Systems, DiveRS 2011, at the 5<sup>th</sup> ACM International Conference on Recommender Systems, RecSys 2011, Chicago, Illinois, USA, 23 October 2011. CEUR Workshop Proceedings 816, CEUR-WS.org 2011