and set higher constraints to the others (i.e., less popular items and inactive users). It is shown that various recommendation models benefit from this strategy. Differentiating regularization weights can be integrated with the other cold start mitigating strategies. See also Collaborative filtering Preference elicitation Recommender system Active learning (machine learning) Five Factor Model References External links http://activeintelligence.org/wp-content/papercite-data/pdf/Rubens-Active-Learning-RecSysHB2010.pdf http://activeintelligence.org/research/al-rs/ Collective intelligence Information systems