Radio programs.
One example would be <em>Lux Radio Theater, </em>sponsored by Lux, a brand of soap. The <em>Jack Benny Show </em>featured ads from its sponsor, Jell-O. Advertising agencies worked to target sponsorship and ads at the target audience of the programs.
Television, by the way, was just beginning in the late 1920s and didn't really become a dominant media until after World War II.
Evidence beyond the Documents:
This additional piece of evidence must be different from the evidence used to earn the point for contextualization.
I would say “chaos is a friend of mine” because i always get myself into trouble and everything turns into chaos
It limited the power of the monarchy and protected citizens' freedom