To accentuate which platform characteristics particularly foster radicalization and extremist dynamics, this contribution investigates the affordances of social media as delineated in contemporary literature, conducting a platform comparison encompassing Telegram, WhatsApp, and X (formerly Twitter). Based on a scoping review, 17 affordances identified from studies researching radicalization dynamics on social media were extracted and categorized. The most frequently mentioned affordances—anonymity, visibility, and collectivity—were then further analyzed concerning their contribution to radicalization and the radicalization potential of these specific platforms. The platform-comparative affordance discussion shows that, although, in principle each of the three compared platforms can foster an environment conducive to radicalization depending on user intention and usage context, the specific characteristics of each platform necessitate a nuanced consideration. On one hand, it is imperative to discern affordances differentially along various dimensions when assessing their implications (e.g., internal vs. external visibility). On the other hand, it is beneficial to consider which affordances emerge from the actualization of other affordances. For instance, collectivity can result from the interplay of several affordances, such as interactivity and anonymity, and can be referred to as a meta-affordance. Furthermore, the analysis shows that platform branding and self-presentation not only affect platform architecture and affordances but also shape users’ perceptions of the platform, thereby influencing the actualization of affordances. This was particularly noted in the literature for Telegram and increasingly for X. Specific assertions, nevertheless, are hindered by the conceptual diffusion of the affordance approach and a lack of empirical analyses directly and systematically examining platform affordances in conjunction with radicalization dynamics.
