Topological Properties of the Core Group in Online Communities

Online communities are self-organized networks with a clear core-periphery structure, where most of the contributions are due to a small group of users known as the core group. Although several methods for detecting the core-periphery structure have been proposed, all of them assume a pre-defined structure of the core group. However, online communities exhibit a wide variety of organizations and shapes, and the patterns of behavior of the core group is continuously changing. This paper investigates the relationship between the global parameters of the community and those of the core group. Findings reveal that the behavior of the core group determines the global structure of the community and therefore, the identification of the core group should consider the global characteristics of the network in which they are contributing.