To understand where we are, we must look at where we have been. For most of the 20th century, popular media operated on a "Cathedral Model." There were a few gates—Hollywood studios, major record labels, network television—and they decided what culture was. If you wanted to be part of the conversation, you watched the final episode of M A S H* or listened to whatever was playing on Top 40 radio. Entertainment was a shared civic ritual.
That era is over.