AND, IN FACT, PRETTY MUCH ALWAYS DO: Facebook Is Big, But Big Networks Can Fall. And though it may take a long time to happen, the unraveling process can be very sudden. “Looking at the most recent Pew study on Internet usage among young people, I see that 71 percent of teens use Facebook, with the median user having slightly less than 150 friends. Forty-one percent of them report that they use Facebook most often. But when I look at a similar Pew study from 2013, it looks to me as if 76 percent of teens were using Facebook, with a median number of 300 friends, and 81 percent of social media users reported that they used Facebook most often. If I were Facebook, those numbers would keep me awake at night — not because Facebook can’t survive with only 70 percent of the market, but because a network that is getting smaller and less valuable to its users is a network that is very vulnerable to disruption.”