Topics Evolution in Online Knowledge Building Communities: A Case Study of Cooking Versus Politics Blogs

Online knowledge building communities (oKBCs) are groups of people that interact, exchange opinions or share expertise in online environments. Profiling an oKBC addresses two main components: members and discussion threads. Their analysis reveals community´s degree of integrativity defined as its capability of assimilating new members who subsequently approach an increasing number of further discussion threads. Thus, timeline analysis of oKBCs emphasizes development patterns of the community. In this study, we propose a parallel analysis of the evolution of community´s discussion threads versus the opinions expressed in posts and comments, as well as modeling the community´s trends from different angles: members´ evolution, posts´ evolution, degree of integrativity, as well as the overall´s community evolution in time. The main motivation of the paper arises from the need of identifying key milestones which determine major changes in how communities evolve in time.