The Impact of Social Media on Public Opinion and Social Movements: A Review of the Literature on Social Media’s Role in Shaping Public Opinion, Political Engagement, and Electoral Outcomes

Over the past two decades, social media platforms have transformed how individuals communicate, organize, and participate in public life. This review synthesizes contemporary literature examining social media’s influence on public opinion, political engagement, and electoral outcomes. Drawing from global research across communication studies, sociology, and political science, it explores how digital platforms facilitate opinion formation, mobilization, and collective action while simultaneously intensifying polarization and misinformation. Classic frameworks such as agenda-setting, framing, and the spiral of silence are revisited within the context of algorithmic curation, virality, and networked publics. Empirical findings suggest that social media both democratizes information dissemination and amplifies ideological divides, challenging deliberative democratic ideals. The review highlights how social media fuels social movements, reshapes campaign communication through microtargeting, and influences electoral behavior. Yet, methodological challenges—data inaccessibility, algorithmic opacity, and cross-cultural variability limit causal inference. The paper identifies emerging hybrid frameworks that merge network analysis with theories of affective publics and digital populism. Future research should emphasize longitudinal, comparative, and interdisciplinary designs integrating computational methods with normative media theory. Overall, this review underscores the dual nature of social media as both an enabler of participatory democracy and a conduit for manipulation and disinformation, calling for greater transparency, regulation, and civic education to sustain an ethical digital public sphere.