Collective empowerment and connective outcry: What legitimize netizens to engage in negative word-of-mouth of online firestorms?

Situated within the context of online firestorms on Chinese social media platforms, this study combines crisis communication literature and connective action logic, to examine what factors contribute to public engagement in negative word-of-mouth (n-WoM) behaviors in online firestorms. In doing so, this study uses a computational method to leverage large-scale longitudinal data of social media users’ digital traces on Sina Weibo and conceptualizes two dimensions of collective legitimacy sources of online firestorms—message and information network legitimacy, revealing their multilayered functional roles in escalating n-WoM engagement. Specifically, our findings suggest that the negativity of social media posts functions as an intensifier of collective message legitimacy escalating publics’ n-WoM engagement, while the observation of a greater cumulative number of negative comments functions as a downtoner for n-WoM engagement. In addition, collective legitimacy is contributed by authority and endorsement sources of information networks. Posts from authoritative sources (KOL, media, and corporation) tend to trigger more subsequent public engagement in n-WoM than posts from endorsement sources (ordinary users). Ability-related online firestorms are more likely to have more n-WoM commenting from netizens than social responsibility-related ones. Distinct differences are found between ability- and social responsibility-related firestorms in terms of the impacts of collective legitimacy sources on eliciting n-WoM engagement.