Top Forty radio invented by Todd Storz and Bill Stewart, of KOWH AM station in Omaha, Nebraska
Top Forty radio was invented by Todd Storz and Bill Stewart, the operator and program director, respectively, of KOWH, an AM station in Omaha, Nebraska, in the early fifties. Like most music programmers of the day, Storz and Stewart provided a little something for everyone. As Marc Fisher writes in his book "Something in the Air" (2007), "The gospel in radio in those days was that no tune ought to be repeated within twenty-four hours of its broadcast--surely listeners would resent having to hear the same song twice in one day."
The eureka moment, as Ben Fong-Torres describes it in "The Hits Just Keep on Coming" (1998), occurred in a restaurant across from the station, where Storz and Stewart would often wait for Storz's girlfriend, a waitress, to get off work. They noticed that even though the waitresses listened to the same handful of songs on the jukebox all day long, played by different customers, when the place finally cleared out and the staff had the jukebox to themselves they played the very same songs. The men asked the waitresses to identify the most popular tunes on the jukebox, and they went back to the station and started playing them, in heavy rotation. Ratings soared.
Read more at the NewYorker.
By the end of the decade, Top Forty was the most popular format in the nation. It thrived in the sixties, but began to struggle with the popularity of FM radio, and the rise of album-oriented rock, in the seventies. Rock music, with its artistic aspirations, didn't fit the nakedly commercial format as well as the bubblegum pop of the pre-rock era had. Also, mainstream pop began to splinter into "adult contemporary," "easy listening," and "urban," among other formats. Rock, meanwhile, gave birth to "classic," "modern," and, in the nineties, "alternative" formats. Top Forty never went away--Casey Kasem's syndicated radio show, "American Top Forty," kept the format going into the twenty-first century--but by the eighties it could no longer claim to be America's soundtrack.
Read more http://www.newyorker.com/reporting/2012/03/26/120326fa_fact_seabrook#ixzz1rQBwK6dO