In this study, mass hysteria will be discussed in the context of online social media and referred explicitly to the out-of-focus phenomenon of public discussion about social issues as social activists advocate on the sphere of social media such as Twitter. In other words, mass hysteria happens when the focus of the public discussion shifts from the targeted critical social issues to other unintended aspects contrary to activists’ expectations. The most recent example is the environmental social movement led by the young Swedish activist Greta Thunberg. While she has been trying to raise governments’ and people’s awareness about climate change, most of the public discussion has been focused on her personal profile, and Thunberg herself has been commodified in the news industry and online social media. Such mass hysteria has not been positive for the progress of environmental activism and public awareness of climate change.

Keyword: audience interaction model, online activism, social network analysis