PBS
Pbs: People and Discoveries: Kdka Begins to Broadcast 1920
This site from PBS details the history of radio and KDKA (Pittsburgh, Pennsylvania) the first radio station to offer programming. Mentions: advertising, NBC Radio, mass culture.
Independence Hall Association
U.s. History: Radio Fever
Radio created a mass entertainment culture that could bridge the gap between those in California and those in New York. Read about the advent of radio stations, and the companies that owned them. See why the federal government had to...