In the early 1920s, the first radio stations were established by radio equipment manufacturers and retailers who offered programs in order to sell more radios to consumers. As time passed, many non-profit organizations followed suit in setting up their own radio stations, and included: schools, clubs and civic groups.
When the practice of sponsoring programs was popularized, each individual radio program was usually sponsored by a single business in exchange for a brief mention of the business' name at the beginning and end of the sponsored shows. However, radio station owners soon realized they could earn more money by selling sponsorship rights in small time allocations to multiple businesses throughout their radio station's broadcasts, rather than selling the sponsorship rights to single businesses per show.