On the Dynamics of Topic-Based Communities in Online Knowledge-Sharing Networks

Online knowledge-sharing networks, such as wikis and Question-Answering (Q&A) portals, offer a rich environment where people can collaborate and share knowledge on specific topics pertaining to their interests and expertise. The continued collaboration of groups of users who share interests in the same topics essentially make up communities, which are here referred to as topic-based communities. Analyzing the dynamics of such communities is key to understanding network processes such as the flow of users and information in the network. In this paper, we study how users relate to topic-based communities and how such relationship shapes long-term community dynamics. Using a large dataset collected from Stack Overflow, a popular programming oriented Q&A site, we investigate several factors related to the evolution of communities in the site, such as user participation and the importance of revisits for community sustainability. Moreover, we develop a model to describe community evolution based on user activity which incorporates key aspects of community dynamics, including member revisits and the flow of users across related communities.