The article deals with the quite topical problem of place and role of mass media in modern society. Investigating the various orientations of the development of such discipline as communication studies, the author gives particular attention to the agenda-setting theory, popular among adherents of different currents in the study of mass communication. Ye.G. Dyakova retraces in what way the study of the effects of mass communication has turned into the study of the public agenda-setting processes. She stresses that the analysis of the said processes has not only theoretical, but also serious applicative significance, for successful application of the agenda-setting technology by mass-media may be fraught with serious influence on public opinion.