This dissertation examines how digital technologies have transformed social movements and online activism, focusing on three central dynamics: (1) framing and counter-framing as mechanisms of racial formation, (2) the role of celebrities in initiating connective action, and (3) how affective economies within fandoms motivate connective action. Through three empirical studies utilizing mixed-methods approaches, including computational analysis of digital trace data and qualitative discourse analysis, this work investigates the intersection of social movements, racial justice movements, and online activism. The first study analyzes anti-Asian racism and resistance during the COVID-19 pandemic, revealing how movements and counter-movements engage in racial framing contests while often developing independent messaging strategies rather than direct counter-framing. The second study examines the impact of celebrity activism through BTS's involvement in the #StopAsianHate movement, demonstrating how high-profile interventions can dramatically amplify movement visibility while potentially overshadowing grassroots efforts. The third study investigates how K-Pop fan communities effectively disrupted the #BlueLivesMatter hashtag through coordinated hashtag hijacking, resulting in significant decreases in police-related content and demonstrating how the strong affective bonds within fan communities can transform hashtag discourse. Together, these studies advance our understanding of how attention may function as a crucial resource in digital activism, how racial projects shape movement framing, and how affective economies within fan communities can be mobilized for social justice. This research contributes to theories of social movements, digital communication, and racial formation while illuminating the complex dynamics of contemporary online activism.