Tracing topic discussions with the event-driven sir model for online forums

Members of online communities on social media (e.g., Web forums) disseminate and receive information by interacting with one another, a situation that provides a good opportunity to examine information diffusion on social media. This study models topic-level opinion diffusion in Web forums through an epidemic model, namely the Susceptible, Infective, and Recovered (SIR) model, which has been used to analyze disease outbreaks and knowledge diffusion. In addition, this study proposes an event-driven SIR model that reflects the effect of a given event on opinion diffusion. The proposed model incorporates the effects of news postings on social media in terms of the growth in numbers of potential authors, the increase in the infection rate for a given topic, and the acceleration of the transition from potential authors to active ones. This study evaluates the proposed model based on a large longitudinal data set from a Web forum of a major company. The analysis results show that the event-driven SIR model performs well in terms of the estimation of the number of authors who discuss a given topic, and outperforms the baseline SIR model in terms of model fit and the forecasting of major hot topics that reflect outbreaks of author participation. This study has some practical business implications: Web forums are places where corporate brands and reputations are formed, as evidenced by forum posts; and Web forums are advertising platforms for contacting audiences and tracking users in order to hone marketing messages and encourage discussions and reviews on a firm's products and services.