<p><strong>Purpose: </strong></p> <p>The current study explores the spillover effects of offensive commenting in online community from the lens of emotional and behavioral contagion. Specifically, it examines the contagion of swearing –a linguistic mannerism that conveys high arousal emotion –based upon two mechanisms of contagion: mimicry and social interaction effect.</p> <p><strong>Design/methodology/approach:</strong></p> <p>The study performs a series of mixed-effect logistic regressions to investigate the contagious potential of offensive comments collected from YouTube in response to Donald Trump’s 2016 presidential campaign videos posted between January and April 2016.</p> <p><strong>Findings:</strong> </p> <p>The study examines non-random incidences of two types of swearing online: public and interpersonal. Findings suggest that a first-level (a.k.a. parent) comment’s public swearing tends to trigger chains of interpersonal swearing in the second-level (a.k.a. child) comments. Meanwhile, among the child-comments, a sequentially preceding comment’s swearing is contagious to the following comment only across the same swearing type. Based on the findings, the study concludes that offensive comments are contagious and have impact on shaping the community-wide linguistic norms of online user interactions.</p> <p><strong>Originality/value:</strong> </p> <p>The study discusses the ways in which an individual’s display of offensiveness may influence and shape discursive cultures on the Internet. This study delves into the mechanisms of text-based contagion by differentiating between mimicry effect and social interaction effect. While online emotional contagion research to this date has focused on the difference between positive and negative valence, Internet research that specifically look at the contagious potential of offensive expressions remain sparse.</p>