Radio in the twentieth century, which you could tune into in your car or at home, had a mass audience and was a collective experience, for good or ill. Radio today, which can be listened to when and how you want it, is a more private and atomized affair. Historian Matthew Lasar discusses the social and political choices and circumstances that led to the decline of broadcast radio and the rise of internet radio.
Resources:
Matthew Lasar, Radio 2.0: Uploading the First Broadcast Medium Praeger, 2016