When Amazon’s Greg Linden applied for a patent for “item to item collaborative filtering” in 1998, he couldn’t possibly have imagined the societal impact it would have. Previously, Amazon had used data based on an individual's purchases to recommend a product they might like; this approach was inefficient because it recommended things that were extremely similar to what the customer had bought before. In fact, this first method of using data was so bad that Amazon was almost better off h...