RSC15: http://2015.recsyschallenge.com/challenge.html
TMALL: https://tianchi.aliyun.com/datalab/dataSet.html?spm=5176.100073.0.0.6abd35eeVkTVx5&dataId=42
RETAILROCKET: https://www.kaggle.com/retailrocket/ecommerce-dataset
DIGINETICA: https://competitions.codalab.org/competitions/11161

30MUSIC: http://recsys.deib.polimi.it/?page_id=54
NOWPLAYING: http://dbis-nowplaying.uibk.ac.at/#nowplaying
AOTM: https://bmcfee.github.io/data/aotm2011.html