This study deals with the stability evaluation of the online community of Russian sociologists. Based on the data from the Facebook group, which consists of 7 years of communication from 2011 till 2018, we constructed the networks based on commenting and reacting. The participants activity includes four main periods for stability evaluation of the community. The blockmodeling discloses the structural patterns of interactions in the community. The results show the "core-periphery" type of the global structure. The core and periphery are structured differently in the networks of comments and reactions. The stability between the positions in the global structure is high and while the structure may vary in some periods, the size of the core and periphery fluctuates. However, the stability within the positions of the global structure is low, according to the modified Rand index (Cugmas, Ferligoj, 2018).