Content area
Social media platforms have fundamentally reshaped the landscape of public discourse, creating dynamic environments where people express opinions, share and consume information, and engage in discussion. However, these platforms are not neutral spaces. Their design, algorithms, and cultural norms influence how users interact, what content is seen, and therefore what themes are discussed and the tone of those conversations. Furthermore, much like in offline settings, people adapt their communication to the norms of their environment. As each platform serves a distinct purpose and cultivates its own atmosphere, users may express themselves differently across them. This thesis explores how online discourse varies across platforms by comparing conversations in Portuguese on Instagram, Reddit, X (formerly Twitter), and TikTok. By collecting a dataset of over 150,000 social media comments, we were able to analyse the sentiment expressed in conversations, the toxicity level of the language used, and the moral framing to understand the tone and character of discussions on each platform. The findings show that tone and style shift significantly depending on the platform: X consistently hosts more toxic and emotionally negative conversations; TikTok fosters a more neutral and less confrontational tone; Reddit contains the highest use of moral language; and Instagram occupies a middle ground across most dimensions. The findings suggest social media platforms foster different communication environments that shape how discussions unfold, influencing both the tone and content of user interactions.