Communities on the Web: Mechanisms Underlying the Emergence of Online Discussion Networks

Abstract

This paper focuses on the mechanisms that underlie the emergence of different types of discussion networks. Previous research showed that discussion threads are significantly longer and wider when certain topics, like politics, are being discussed. We consider the self-selection of users as one possible mechanism for the emergence of these structural differences. If users decide to take part in some discussions but not others, thus specialising in certain topics, their differences might lead to the emergence of different networks. We do not find conclusive evidence for the self-selection argument, but we do find time differences across topics: users systematically invest more time in certain discussions (i.e. those producing longer threads). Our analyses strengthen the original finding that it is the topic of the conversation, not the characteristics of those participating, what drives the emergence of certain types of networks: some topics invite users to keep conversations alive for a longer period of time. This, we conclude, suggests that users engage in different patterns of interaction depending on the context, much in the same way as different roles are played in different social settings. Future lines of research are considered.