This article explores the mobilization power of online grassroots discourse often criticized by researchers as a threat to the Habermasian public sphere. The study takes a historical perspective and attempts to see elements of grassroots discourse as a recontextualization of Chinese revolutionary discourse. The high-profile Yao Jiaxin murder case is taken as the background, and an online open letter and its reply that have attracted wide attention to the event are selected as data for analysis. The theoretical approach utilizes Fairclough’s discourse analysis investigating discursive transformation in social and cultural change, and his synthesis of intertextuality analysis and Gramsci’s hegemony theory is found to be particularly helpful in the discussion. Two aspects of the text will be analyzed in detail – the emotional appeal and the strategy of inclusion/exclusion based on class division, as well as how such rhetoric is challenged and marginalized in new social contexts.