What is "plugola"

n. (context chiefly US English) undeclared or illicit publicity or product promotion, especially on radio or television. (from 20th c.)

Plugola is the illicit business practice of endorsing a product or service on radio or television for personal gain, without the consent of the network or stations. “Pluggers” have been known to accept bribes of money, alcohol, or free products and services. This contrasts greatly from commercial sponsorship because the benefits of the endorsement go to the individual talent or programmers, while the stations and networks receive no revenue.