It's mid-afternoon on a weekday. When you browse to Netflix's catalog of instant streaming video, a complex series of algorithms go to work, formulating recommendations based on the time of day and the device you're currently using. Then the recommendations appear. How about a nice daytime soap opera? Maybe some old 80s sitcoms? Pleasant, afternoon time-killers. Tune in at night, though, and those recommendations will change. Oscar-winning dramas appear with a few action flicks and dramas peppered in. These are movies Netflix knows you'll want to pay attention to. It doesn't just know what you'd like to watch--it knows when and where.
Netflix doesn't work this way yet. But it's probably going to in the next few years, judging by this Wired interview with a pair of Netflix engineers. They estimate 75 percent of Netflix viewing activity is driven by recommendations, which means a huge chunk of Netflix's 800 engineers are working around the clock to make their recommendations smarter. One way they do that is paying very close attention to what you watch.
Netflix tracks "what you played, searched for, or rated, as well as the time, date, and device." Engineering director Xavier Amatriain told Wired "We have been working for some time on introducing context into recommendations. We have data that suggests there is different viewing behavior depending on the day of the week, the time of day, the device, and sometimes even the location. But implementing contextual recommendations has practical challenges that we are currently working on. We hope to be using it in the near future."
For now, Netflix recommendations are still heavily based on tags created by more than 40 part-time media junkies, who identify the key characteristics of the Netflix library. They're responsible for the categories Netflix is so well-known for, like Politically Charged Action Thrillers or Imaginative Time Travel Movies from the 1980s. Similarities like lead actors or directors aren't necessarily enough to earn a Netflix recommendation; a movie like Spielberg's Schindler's List doesn't have much in common with 1942, which he also directed.
Another interesting tidbit from the interview: Star ratings, which were once key to Netflix's business, don't matter too much anymore. When users primarily rented DVDs, they had an investment in the time it took to receive the disc and cared more about the end result. With streaming video, if users don't like something, they just switch to a different video. And Netflix is watching.