Political discourse on social networking sites: Sentiment, in-group/out-group orientation and rationality

The news feeds of two U.S. politicians' Facebook sites were examined across 22 months leading up to an election in order to explore changes in social-network-mediated public political discourse over time. Changes over time were observed in who was being addressed and in the affective valence of comments. A complex flow of attention between in-group and out-group concerns was observed, with in-group comments dominant both in early and late phases. Also, positive comments decreased and negative comments increased over time. These phenomena, dubbed "reflection-to-selection" and "converging sentiment", were refined to explain the observed nonlinearities. The flow of rational versus affective comments in politicians' Facebook data across time was also explored. Comments reflecting cognition were more prevalent at all times than comments reflecting affect, but their distribution also varied in complex ways over time. Finally, the concept of potential public sphere in contrast to realized public sphere in virtual spaces is introduced.