The economic content of social networks was found out as a channel and a tool of marketing communication that unites customer and marketer according to supply and demand of the products of international companies (ICs), which key (basic) features are the following: interactivity, high dynamism and large scale of communication of different groups of customers and marketers of the company, as well as the genesis of their formation. Social networks are studied as a tool of the ICs’ marketing communication system which includes the following set of communication methods: building brand communities, work with the blogosphere, personal branding, unconventional activities, reputation management and communication means: advertising in social networks, public relations in social networks, viral campaigns, generation of leads and community building; differentiation of social networks in the structure of the ICs’ marketing communications was examined as well. The differentiation was made and the features of the use of social networks in the structure of the ICs’ marketing communications were analyzed. It was found that the majority of international companies actively use social networks for carrying out communications, among which the most applicable network is Facebook. The innovative orientation of social networks as means of implementation of the ICs’ communication policy was identified; it consists in the use of strategic innovation management aimed at the use of innovative tools to promote via social networks. The transformation of the relation of social networks and traditional tools of the ICs’ marketing communication consists in the use of advertising, PR, holding mass events, personal sales, sales promotion, direct marketing and other traditional tools of marketing communications in the plane of interaction with consumers in social networks. The economic and mathematical model of research on the SMM effectiveness is developed which shows the ratio of return on financing of (costs for) the formation of content in social networks and targeted advertising in social networks, and the effectiveness of such means of social communications (criteria - the number of indexed pages (various search engines), the number of references to the names of the company (brands), information dissemination speed, functionality, and the like) and the individual factors of the SMM efficiency (number of members of communities, members responding to the content, audience cover, transitions to the corporate website, audience inflow/outflow) by means of which it was found out that the development of search content of social networks is more effective than the use of targeted advertising.
