[...] even as an algorithm mindlessly implements its procedures--and even as it learns to see new patterns in the data--it reflects the minds of its creators, the motives of its trainers. Both Amazon and Netflix use algorithms to make recommendations about books and films. [...] the algorithms make fundamentally different recommendations. Amazon steers you to the sorts of books that you've seen before. Netflix directs users to the unfamiliar. There's a business reason for this difference. Blockbuster movies cost Netflix more to stream. Greater profit arrives when you decide to watch more obscure fare. [...]