In the early 1950s, the DuMont Television Network began the modern practice of selling advertisement time to multiple sponsors. Previously, DuMont had trouble finding sponsors for many of their programs and compensated by selling smaller blocks of advertising time to several businesses. This eventually became the standard for the commercial television industry in the United States. However, it was still a common practice to have single sponsor shows, such as The United States Steel Hour. In some instances the sponsors exercised great control over the content of the show – up to and including having one's advertising agency actually writing the show.
The single sponsor model is much less prevalent now, a notable exception being the Hallmark Hall of Fame.
Cable television from the 1980s
The late 1980s and early 1990s saw the introduction of cable television and particularly MTV. Pioneering the concept of the music video, MTV ushered in a new type of advertising: the consumer tunes in for the advertising message, rather than it being a by-product or afterthought. As cable and satellite television became increasingly prevalent, specialty channels emerged, including channels entirely devoted to advertising, such as QVC, Home Shopping Network, and ShopTV Canada.