The 1920s saw the birth of a new mass medium, radio. By 1928, the United States had three national radio networks — two owned by NBC (the National Broadcasting Company), one by CBS (the Columbia Broadcasting System). Though mostly listened to for entertainment, radio's instant, on-the-spot reports of dramatic events drew huge audiences throughout the 1930s and World War II.
Radio also introduced government regulation into the media. Early radio stations went on and off the air and wandered across different frequencies, often blocking other stations and annoying listeners. To resolve the problem, Congress gave the government power to regulate and license broadcasters. From then on, the airwaves — both radio and TV — were considered a scarce national resource, to be operated in the public interest.
After World War II, American homes were invaded by a powerful new force: television.
The idea of seeing "live" shows in the living room was immediately attractive — and the effects are still being measured. TV was developed at a time when Americans were becoming more affluent and more mobile. Traditional family ways were weakening. Watching TV soon became a social ritual. Millions of people set up their activities and lifestyles around TV's program schedule. In fact, in the average American household, the television seems to be watched 7 hours a day.
Television, like radio before it focused on popular entertainment to provide large audiences to advertisers. TV production rapidly became concentrated in three major networks — CBS, NBC and ABC.
A 30-second commercial on network television during prime evening viewing time costs $100,000 or more. A single half-hour show costs hundreds of thousands of dollars to produce .
At first it was thought that the popularity of TV and its advertiser support-would cause declining interest in the other media. Instead, TV whetted the public's appetite for information. Book publishers found that TV stimulated reading . Though some big-city newspapers closed others merged and new ones opened in the suburbs. And while a few mass circulation magazines failed, hundreds of specialized magazines sprang up in their place.
Technology continues to change the media. Already half of American homes subscribe to cable TV, which broadcasts dozens of channels providing information and entertainment of every kind.
In addition to the 1,140 television stations offering programming in 1990, there were 9,900 cable operating systems serving 44 million subscribers in 27,000 communities. These subscribers paid an average fee of $15 per month to watch programs not offered on commercial channels. One cable network offers news 24 hours a day. Some communities have publicly controlled cable television stations, allowing, citizen groups to put on programs.
Still, the long awaited dream of a home completely "wired" with computer and cable TV links is a long way off. Cable TV, for instance, has not provided significantly better programming, only more of the same. The reason critics say, is economics — the relentless pressure of seeking large audiences in order to attract advertisers.
This pressure for profits has caused concern over one о f the most important trends in the media today: The ownership of the news media, experts say, is being concentrated in fewer and fewer hands. Chains — companies that own two or more newspapers, broadcast stations or other media outlets — are growing larger. They are forcing out independent, often family-owned news media. That means that most American communities are served by news media owned by outsiders.