You enjoy the shows that Netflix acquires, but you might not know that Netflix monitors piracy sites for shows being downloaded, in order to decide what to acquire. The video streaming service uses statistics relating to video piracy as a social barometer, as well as other metrics, to figure out what shows and films it needs to secure for your viewing pleasure.
Truth be told, there is probably no better indicator for what shows are hot. Vice President of Content Acquisition Kelly Merryman recently cited the example of Prison Break in an interview with Dutch site Tweakers, as being popular on torrents in the country, so they acquired the show. Netflix also takes into account other shows that are heavily watched on the service, and of course the ones that no one is watching.
Even when a show is popular in piracy, there is no guarantee that it will show up on Netflix. Sometimes there are exclusivity deals that get in the way, like with Game of Thrones.
Source Electronista