Promotion through radio has been a viable advertising option for over 80 years. Radio advertising is mostly local to the broadcast range of a radio station, however, at least three options exist that offer national and potentially international coverage. First, in many countries there are radio networks that use many geographically distinct stations to broadcast simultaneously. In the United States such networks as Disney (children’s programming) and ESPN (sports programming) broadcast nationally either through a group of company-owned stations or through a syndication arrangement (i.e., business agreement) with partner stations. Second, within the last few years the emergence of radio programming delivered via satellite has become an option for national advertising. Finally, the potential for national and international advertising may become more attractive as radio stations allow their signals to be broadcast over the Internet.
In many ways radio suffers the same problems as television, namely, a mass medium that is not highly targeted and offers little opportunity to track responses. But unlike television, radio presents the additional disadvantage of limiting advertisers to audio-only advertising. For some products advertising without visual support is not effective.