1. INTRODUCTION
While traditional recommender systems are commonly trained through users’
feedback on the recommended items, recommenders (and specifically mobile recommenders)
increasingly also employ users’ demographical and contextual data. Those
data allow them to instantly generate recommendations that are relevant to the user
and to the situation in which the recommender system is being used [Adomavicius
and Tuzhilin 2011]. Privacy research however indicates that quite a few people feel