ABSTRACT
Before television, there was radio advertising and fi lm advertising in movie houses. You still see local ads in some movie theaters before the program starts. So the principle of selling time between programming for commercial messages grew up with the visual media. A format that is probably unique to television was developed to deliver short visual commercial messages very effi ciently and effectively in breaks between programs. The airtime was sold to advertisers to generate the operating revenue and profi t for the television companies. This is now the principal business model for mainstream media that are free to the viewer.
