Parallel and Distributed Collaborative Filtering: A Survey
  Collaborative filtering is amongst the most preferred techniques when implementing recommender systems. Recently, great interest has turned towards parallel and distributed implementations of collaborative filtering algorithms. This work is a survey of the parallel and distributed collaborative filtering implementations, aiming not only to provide a comprehensive presentation of the field's development, but also to offer future research orientation by highlighting the issues that need to be further developed. 
Efthalia Karydi and Konstantinos G. Margaritis
cs.IR cs.DC