Social networks are currently one of the most studied structures for information and knowledge exchange. These structures are very well described in terms of their static structure, this article attempts to propose the model of their dynamic behavior and the spread of information and knowledge in these networks. The heuristic event based model of the individual behavior in the network using the message passing will be presented. The main idea of the model is agent’s need for information and knowledge in specific situations. On that is based multiagent model of the social network used for information exchange, which has been practically implemented an will be presented as well as some of its simulation outputs for tasks testing the dynamics of social networks.