Event-related crowd activities on social media

Social media like Twitter has been prevalently used for observing the behaviors of a large number of people. The availability of such behavioral trace data leads to an emergent interest in studying “crowds” in many contexts related to real-world events ranging from emergencies to ceremonies. There is, however, a lack of understanding about how different questions regarding crowd activities were asked and approached. This chapter provides a lens into event-related crowd activities within the social media domain by classifying literature into three themes: (1) crowds as event sensors, (2) crowds as event predictors, and (3) crowd characterization around events. Using the classification, it can be revealed that there is a gap between understanding and harnessing crowd activities. Several theoretical and methodological questions and implications are discussed. This chapter concludes with suggested future directions toward better gaining insights from social media crowds