Commercial radio stations began broadcasting in the early 1920s, but it would be over a decade before the concept of selling over-the-air advertising would catch on.
By the 1930s, it was common practice for programs to be owned and produced by the advertiser, who in turn leased production facilities and air time from the network.
In the early 1950s, the DuMont Television Network began the modern trend of selling advertising time to multiple sponsors.
DuMont had trouble finding sponsors for many of their programs and compensated by selling smaller blocks of advertising time to several businesses.
An estimated 53% to 60% of Public Broadcasting Service (PBS) television's revenues come from private membership donations and grants,[1] making sustaining programs viable in that sector.
Most stations solicit individual donations by methods including fundraising, pledge drives or telethons which can disrupt regularly scheduled programming.