A recommender system is super hard because humans are hard. Even if the problem is well defined, like movie recommendations, it is exceptionally hard. Read abou

A recommender system is super hard because humans are hard. Even if the problem is well defined, like movie recommendations, it is exceptionally hard. Read about the Netflix challenge https://en.wikipedia.org/wiki/Netflix_Prize https://en.wikipedia.org/wiki/Netflix_Prize which took some of the worlds best researchers (trying to win $1MM) 3 years to increase Netflixes algorithm by 10%.