This year’s Super Bowl, as has become custom, brought Americans together like no other event. There was the game, which in the end turned out to be pretty exciting. There was the power outage, which was pretty dramatic, too. There was Beyoncé’s half-time performance. And there were of course the ads. In an age where TV audiences keep shrinking and fragmenting, the Super Bowl appears to have once again set a viewership record. It is a spectacle that has become so popular that many of us pay attention mainly because everyone else is paying attention, too — a self-reinforcing network effect that can be really hard to break.