Disruptive Gateways: Unravelling Political Discourse through Social Media Hyperlinks and Alternative Media Amplification

Over the last decade, social media have become a dominant tool of political communication. Social media constitutes an opportune medium for political actors that offer direct access to audiences, circumventing the traditional media’s gatekeeping monopoly. This paper examines the role of hyperlinks in politicians’ social media activity, a factor that has been largely overlooked so far. We argue that social media platforms not only allow politicians to bypass conventional modes of journalistic gatekeeping but they also create gateways to steer their audiences towards sources that resonate with exclusively partisan worldviews, potentially disrupting and polarizing public discourse. To assess this claim, this paper makes use of large-scale web data collection and machine-learning combined with manual source classification to analyse over 10 million tweets by MPs and party headquarters in Germany and the United Kingdom over a 10-year period. The analysis seeks to elucidate the prominent themes and policy areas used by various political actors to amplify content sourced from alternative media outlets and guide their audiences toward sources that solely echo with partisan perspectives. We investigate strategic information-sharing, specifically mainstream and alternative media, to gain a better understanding of patterns of issue-specific dissemination. Our findings have direct implications for the moderation policies of social media platforms, serving as protective measures for upholding the credibility of authoritative information sources and acting as gatekeepers in online discourse, especially with respect to the content social media users share, not only the content they generate.