The expansion and accessibility of Internet technology has allowed a new look at social networks. A few decades ago, this online service was more entertaining in nature. However, today, with increasing transmission rates and the possibility of real-time communication, social networks, on which platform a poll or vote can be easily organized, become a powerful mechanism for achieving consensus in decision making process. The paper offers an overview of the known models of group decision making (GDM) and a formal description of the decision-making algorithm developed on the basis of the overview taking into account a large amount of data in a social network. A feature of the algorithm is the ability for an expert to choose a limited subset of interest from a huge number of alternatives, as well as taking into account network scaling in terms of the number of experts involved in the GDM process. The method of extrapolating the values of the estimates for network scaling is proposed. A numerical case for an illustration of the algorithm is developed and presented. © 2019 Federal Research Center "Computer Science and Control" of Russian Academy of Sciences. All rights reserved.