What Makes Hyper-local Online Discussion Forums Sustainable?

Despite the global success enjoyed by a few social media platforms such as Wikipedia and Facebook, many platforms that target geographically bounded communities struggle to sustain users\´ participation over time. Understanding what makes such "hyper-local" communities sustainable can lead to better technologies for encouraging community awareness and civic participation. However, little is known about how the social structure of such online communities impacts their sustainability. In this study, we conceptualize sustainability through the aspects of viability and performance. We measure three system-level factors that affect sustainability, including network size, connectedness and centralization, which capture the communities\´ social structures. We test our hypotheses on the longitudinal data collected from E-Democracy.org. Our results indicate that network connectedness and centralization are positively associated with performance but not with viability. The findings reveal a system design dilemma for hyper-local forums. We discuss the implications and potential solutions to overcome the sustainability challenge.