AAAI Publications, Sixth International AAAI Conference on Weblogs and Social Media

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Mixed Membership Models for Exploring User Roles in Online Fora
Arthur J. White, Jeffrey Chan, Conor Hayes, Brendan Murphy

Last modified: 2012-05-20


Discussion boards are a form of social media which allow users to discuss topics and exchange information in a complex manner, in a number of different settings. As the popularity of such message boards has increased, communities of users have emerged, and several prominent types of social role have been identified, such as Question Answerer, Celebrity, Discussion Person and Topic Initiator. Recent studies have noted the structural similarity of the egocentric network of users assigned the same role by qualitative criteria. In this paper a methodology is developed with which to cluster together users with similar ego-centric network structures. This is achieved using a mixed membership formulation which allows for the fact that different groups of users may have characteristics in common. The method is then applied to data taken from, a medium sized message boards website. Prominent clusters of users are identified and discussed, and illustrative examples of user behaviour provided. The type of interaction, both locally and globally, taking place within forums is examined.


forums; mixed membership; role analysis; variational Bayes

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