Lectures covered some of the developments in early radio -- notably the rise of advertising, advertiser control over scripts and programming (with shows such as Cavalcade of America) and the resulting content mix (comedy, variety shows, soap operas, etc.).

With the rise of television, radio as a mass entertainment medium all but died. Most major performers moved from radio onto television and television emerged as the mass entertainment medium of the post-World War II era. Radio essentially reinvented itself in the 1950s, developing into a segment or niche medium. Rather than attempting to broadcast programs to all of the listening audience, radio instead sought to develop specific audience segments. The most successful of the early segments was Rock and Roll -- and the idea of playing the "Top 40" records/songs each week.

Richard Campbell (in Media and Culture) notes that the term Top 40 derives from the number of records stored in a jukebox. Several entrepreneurs got the idea for the Top 40 format by watching bar patrons and waitresses (in restaurants, bars and diners) playing the same songs ovl5er and over. Top 40 emerged from this -- a short play list (of 40 songs) played throughout the day. There was some rotation in the mix; listeners stayed tuned to hear their favorite songs.

Further segmenting developed by time of day (and by who would be listening at that time). Early morning radio has often focused on "drive time" -- the morning commute, offering news, traffic information and other content for commuters (an audience dominated by men). Daytime radio has sought out women listeners (even though the number of women working in the home has declined greatly, this is still a substantial audience). And we’ve seen further development of radio segments since the rise of Top 40.

Formats include Country and Western, Top 40, Nostalgia (mostly for Baby Boomers), Religious, Easy Listening (known derisively as "elevator music" by some), News/talk radio, Progressive Rock and Soft Rock.

One of the most popular contemporary formats is MOR (middle of the road) or Adult Contemporary (AC). It reaches about a fifth of all listeners; the audience tends to skew older (with a lot of listeners over 40). Other formats include Spanish-language radio, Urban Contemporary (rap, blues).

Radio today is a highly profitable medium. In 1996, total radio billings were $11.4 billion. Advertisers bought local time worth $9.1 billion (80% of all billings); national spots worth $1.9 billion and network time worth $426 million. Radio is an attractive advertising medium. Radio ads are inexpensive to produce and thus can be changed, updated and specialized fairly easily. Radio time is generally inexpensive to buy, too (especially compared to television).

For many years, the Federal Communications Commission limited the number of radio stations one person or company could own to one AM and one FM locally and seven AM s and seven F Ms nationally. Controls were almost totally eliminated in the Telecommunications Act of 1996. There are no national ownership limits today; one person or company can own as many as eight stations in one market (depending on the size of the market).

Talk radio is the fastest growing radio format since the Top 40 format in the 1950s. Its roots go back to the 1920s and 1930s, when gossip columnists on radio (such as Louella Parsons and Walter Winchell) provided extensive "news" about celebrities and Hollywood.

Rush Limbaugh led the trend of popular conservative talk radio show hosts in the 1990s. His success created spinoffs (as in television and other media): G. Gordon Liddy, Oliver North and others joined the radio ranks with their mix of opinion, news commentary and call-in-discussion.

Limbaugh, at his peak, was syndicated to 660 stations, reaching an estimated 20 million people a week. A survey by one news organization found that 44 percent of Americans got most of the political information from talk radio. On AM radio, talk became the most common format in the 1990s.

Another study, though, noted that the political talk show audience is largely white, male, Republican and financially well off. It is much more politically engaged that the general population, but generally on the right wing of the political spectrum. These are people who distrust the mainstream media, which they see as biased toward liberalism.

Many of the 1990s talk show hosts were conservative. In 1998, the National Association of Radio estimated that 75 to 80 per cent of the radio talk show hosts were taking a conservative stance.

By the late 1990s, there seemed to be a bit of a trend away from a lot of politics in talk radio-- and a trend toward commentary and advice on every day life issues. Dr. Laura Schlesinger led this trend; her show (beginning in 1994) deals with love, marriage and family responsibility. Critics have questioned the credentials of "Dr. Laura" (she has a Ph.D. in physiology, not psychology) while others were put off by her sharp retorts and insults to some listeners. Her supporters like her because of her sharp edge.

Why has talk radio been so popular? There are several reasons.

First, political talk radio boomed in the late 1980s and early 1990s because many had come to believe (correctly or not) that the mainstream media were too liberal. Talk radio provided a forum for people who did not see their views routinely represented in the mainstream media.

Second, radio has always been a medium of great intimacy. There’s a personal nature to the medium that is often lacking in other media. Talk radio highlights that intimacy.

Third, there are very few opportunities for people to "talk back" via the media. Through call in shows, listeners can give their opinions, rant -- and be listened to. Talk radio is one of the few really interactive forums in media today.

Shock Jocks refer to people such as Howard Stern -- radio personalities who are outrageous, rude, and often crude. And many of these radio hosts are extremely popular. Stern took poorly rated WXRX in New York to a top rating in its market; he is syndicated throughout the country. He is excessive at times: praying for cancer to kill public officials he does not like, and he jokes constantly about sexual and other body functions. He insults guests and callers and tells jokes that are sexist and homophobic. But that’s part of his attraction to some listeners. The FCC has fined stations that carry his shows more than $1 million, a move called harassment and censorship by his supporters.