To those who grew up in the 1950s, there were three networks that every American watched or listened to for news and entertainment. The government operated a fourth public station. And four decades later a fifth network joined the team. Newspapers from New York, Washington, and other cities big and small told their readers all the news that was fit to print. Corporations and governments told the people what the news was and how to think about it, and entire wars were won or lost on the field of public opinion driven by the networks. But that monolithic structure didn’t last very long.