Excerpt from this article:
Stars were on the out for several reasons. For one, Netflix was transitioning from a DVD rental business to a streaming company. It was less reliant on you telling it what you liked (via ratings), because it could already tell what you liked — simply by analyzing what you had watched.
And there tended to be a gulf between the two behaviors. People rated aspirationally, but they watched situationally. Yes, you did give That Important Documentary five stars when you got around to watching it, but at the end of a trying day at the office, you more often settled on viewing some pleasing pap like “The Ridiculous 6.”