On the basis of scientific publications of Russian and American researchers the author reveals content and functional features of modern public service announcements and ads in the USA and Russia, offers a definition of the public service announcement as a form of advertising communication, identifies its general and special functions (educational and intellectual), distinguishes a set of motivations that explains the targeting factors. Dominant parameters of public interest announcements and ads, the role of the state in their production, the channels of their distribution that might raise the amount of mass addressees, efficiency of socially important content delivery as well as public acceptance patterns are in the focus of attention. The author's observations and analysis of social advertising posters in the USA and Russia are presented as a set of topics that reflects the involvement of both countries in the global issues discussions and national peculiarities in their consideration. The conclusion states correlation between topical content and extralinguistic factors which explains qualitative differences between public service announcements and ads in the USA and Russia.