In this work, the concept of a system for analysing social relations between entities using the social network analysis and multi-agent system approaches is presented. The following problems especially appear within the domain of our interests: identification of the most influential individuals in a given society, identification of roles played by the given individuals in that society and the recognition of groups of individuals strongly connected with one another. For the analysis of these problems, two application domains are selected: an analysis of data regarding phone calls and analysis of Internet Weblogs.