M.A. To understand advertising content, we need to look at in several ways. An earlier lecture differentiated between Advertising, Public Relations, and News. The first chapters of your textbook describe the communications process and how people use mass communications.
Later chapters explore media businesses and the part advertising plays.
At the end of the lectures you'll find a bibliography for further research. To recapitulate, the difference between advertising and news is that sponsors PAY for ads. It's often easier to see the techniques at work on older posters and advertising, since they seem more obvious. Also works with something that is disrespected to the latter rejected. Watch posturing politicians and see them standing in front of symbols of authority.