Platform-based diffusion-proofing: Digitally mediated discursive practice and China's prevention of protest spillover during Hong Kong's Anti-Extradition Bill Movement

Based on the example of mainland China's online diffusion-proofing practices against Hong Kong's Anti-Extradition Bill Movement, we identify a platform-based tactic of diffusion-proofing. We argue that this tactic manifested the orchestration of top-down statist governance and bottom-up grassroots practices, as well as within-border and cross-border discursive dynamics. Facilitated by the technical affordances of social media platforms, a faction of netizens both from mainland China and Hong Kong followed the state and its agents online to co-construct discourses for preventing the potential spillover of the Movement to mainland China. We further suggest that this tactic was enabled by the hybridization of both technical logic and discursive logic. The platform affordances, especially different types of hashtags, allowed the state and its agents to practice digitally mediated discursive production, reacting to the momentum of the Movement. As a result, a discourse was constructed, which delegitimatized protest actions and ignited nationalistic sentiment for the purpose of diffusion-proofing.