Political advertising on social media exposes how parties tailor messages to different audiences within algorithmic environments. This study analyzes over 45,000 Facebook ad campaigns from populist and mainstream parties across five EU countries, showing how populist movements achieve disproportionate reach through targeted appeals to gendered and age-specific demographics. The results highlight how populist communication adapts to platform logics, reinforcing national narratives while remaining ideologically fluid.

Opinion change is rarely studied as a driver of behavioral transformation. Using longitudinal Reddit data from r/ChangeMyView, this research examines how self-reported opinion shifts predict subsequent changes in information consumption. The analysis shows that users alter their participation across communities according to the persuasive and propagandistic features of prior discussions, illustrating how moments of reflection can reorganize digital attention networks.

Digital communities can replicate the social mechanisms of peer support traditionally found in offline recovery groups. This study analyzes interactions among Reddit users in opioid recovery, uncovering patterns of trust, reciprocity, and behavioral reinforcement that help sustain participation and progress. The results indicate that online spaces can act as functional surrogates for support networks, providing structure and belonging to individuals facing stigma and isolation.

Language encodes the social processes behind persuasion and disagreement. Drawing from Habermas’ theory of communicative action, this study uses natural language processing to model how intent and tone influence opinion change in online debates. The results show that expressions of knowledge, empathy, and similarity are most effective at fostering change, revealing how communicative structure mediates social learning in digital spaces.

Online political engagement depends on how users shift attention across communities. This paper proposes an attention-flow graph that captures user migration between subreddits, identifying gateways and bridges that connect mainstream, conspiratorial, and extremist spaces. The analysis shows how conspiracy forums can act as intermediaries in radicalization pathways, mapping the structural channels through which political audiences reorganize.