A is the means by which one party attempts to convince or entice another into purchasing a particular product or service. It differs from the sort of one-on-one sales pitch an individual might encounter at the point of sale in that it addresses a larger, more general audience. Advertising therefore differs substantially from persuasive conversation insofar as it relies entirely on mass media and consequently on widespread social meanings rather than personal or idiosyncratic motivations for purchasing. Historically, advertising was first introduced in print media. Early newspapers were short broadsheets entirely filled with text; newspaper revenues came only through reader subscription. The advent of newspaper advertising created a dual revenue system in which income was gathered from both subscribers and advertisers. The advertising message was piggybacked on the stories. Newspapers consequently sold two commodities: to the subscriber, they sold stories; to the advertiser, they sold access to a market of a certain sort. With the advent of photography and photolithography, the illustrated news broadsheets gave birth to the modern magazine. While retaining a partial orientation, the magazine fostered review, biographical pieces, analytic features, and photo spreads. More important, technical innovations permitted more sophisticated advertising—employing eye-catching full-page photographs. Approximately two-thirds of newspaper and magazine revenues are now generated from the advertising. A magazine's primary market has thus shifted from readers to advertisers.