At BottleRock Napa Valley, the obvious headliners were on stage. The less obvious one was overhead, under tents, behind stages, near point-of-sale terminals, and in thousands of pockets: the network. That may sound like something only a data person would say, and fair enough. But once you spend time inside a live event like BottleRock, you start to see how much of the experience depends on invisible systems working together.