It is the extent on how the manipulation of information can produce effects on the actions, behavior and/or opinions of the public. Some advertising and public relations firms engage in manipulation to increase the degree of influence or impact to the public.
Examples:
If the general infomercial released for disaster preparedness is misinterpreted, the public might panic which will produce a negative impact despite the good motive or purpose.
Some commercials, like those involving cigarettes and liquor, can influence people to consume things that could be potentially dangerous to their health. It can also influence young people to try it too.