There have been many disruptions of the functioning of the discursive public sphere by new communications technologies. The most recent significant one was the early-twentieth century disruption by radio. The very sharp and witty Maciej Ceglowski provides us with a brief introduction:

Maciej Ceglowski: Legends of the Ancient Web: "It doesn't take long for politically talented people to discover how to use radio for their own ends. One of these early pioneers in the United States is Charles Coughlin, a Catholic priest and early religious broadcaster who notices that his angry rants on political topics net him a much bigger audience than his discourses on religion. By the middle of the 1930's, Coughlin has an active audience of ten million tuning in to hear him rail against against bankers and international conspiracies, in a way that sounds uncomfortably familiar in 2017. Here's Father Coughlin at the top of his game, yelling about banks...

...The other great political radio talent in America is the new President, Franklin Roosevelt. Facing a hostile press controlled by his opponents, Roosevelt decides to speak directly to the people in a series of what he terms "fireside chats". These are not delivered in the bombastic style of political speeches, or in the angry right-wing talk radio style pioneered by Father Coughlin, but conversationally, as if the President were at home with you in your parlor. Roosevelt exploits the intimacy of radio, speaking to people gathered in their homes, in the evening, in the company of friends and loved ones. Here's what his first fireside chat sounded like. You wouldn't think that a lecture about the banking system could be very appealing. But in an atmosphere of crisis, people listen. For the first time, they can directly hear their leader discuss an issue of enormous consequence to their lives, in their own homes. These fireside chats help win Roosevelt a lasting popularity that will confound his enemies over the years. He will go on to win re-election three times.

Saul Bellow wrote about what it was like to experience one of Roosevelt's broadcasts:

drivers had pulled over, parking bumper to bumper, and turned on their radios to hear Roosevelt. They had rolled down the windows and opened the car doors. Everywhere the same voice, its odd Eastern accent, which in anyone else would have irritated Midwesterners. You could follow without missing a single word as you strolled by. You felt joined to these unknown drivers, men and women smoking their cigarettes in silence, not so much considering the President's words as affirming the rightness of his tone and taking assurance from it.

Right there, in that Saul Bellow quote, we also find a warning about the danger of this intimate new medium. "Not considering but affirming." This is the power that radio has to persuade through emotion, repetition, familiarity, and tone, rather than facts or argument. A good radio broadcast makes you feel like a part of something bigger, even as you listen alone.

Europe also finds a first-class radio genius, in the person of Joseph Goebbels, the Nazi propaganda minister. One of Goebbels's first acts after the Nazis seize power in 1933 is to start the production of cheap radios, the Volksempfänger, or "people's receiver". Goebbels believes it essential to the success of National Socialism that there be a radio in every home, and a loudspeaker at the workplace...