Gun Control Agendas in Networked Digital Environment: An Intermedia Comparison Between News Outlets, Activism Media, and Ephemeral Websites.

This study investigates the intermedia agenda-setting dynamics of the 2018 U.S. gun control movement, specifically the March for Our Lives (MFOL) campaign, by analyzing the roles of activism/advocacy media and ephemeral websites in shaping public discourse across news outlets. Using structural topic modeling and cross-lagged correlation analyses on Meta's Facebook URLs Share dataset, the research finds that activism media prominently set protest-related and policy-focused agendas that influenced other media types, while ephemeral websites tended to propagate conspiratorial and misinformation narratives, potentially disrupting the movement's messaging. The study highlights reciprocal agenda-setting relationships among various media actors, noting that ephemeral websites both influence and are influenced by other media, complicating the information environment surrounding social movements. These findings contribute to understanding how alternative media actors participate in agenda-building and underscore challenges activists face in managing misinformation within today's hybrid digital media ecosystem.