Which Types of Brazilian Telegram Groups are More Susceptible to being Politicized?

Online social networks (OSNs) serve as environments for various forms of social interaction, ranging from influencers interacting with their fans to more peer-to-peer forms of community debate. Instant messaging platforms are an example of spaces used for more horizontal peer-to-peer conversations. During election cycles, these digital spaces often become exposed to political manipulation and propaganda based on social ties. Regardless of their original purpose, politics can co-opt the group discourse in a process of politicization. Although studies explored the politicization of non-political topics such as vaccines and political coordination in OSNs, the politicization of non-political spaces themselves remains overlooked. This study investigates the politicization of non-political public Telegram groups in the context of the 2022 Brazilian elections. Using a curated set of Brazilian Telegram groups, we extract the data via the Telethon API and apply a BERT model to detect political messages. Our findings indicate a 60% increase in political content, primarily occurring in groups with themes indirectly related to politics (e.g., News) or in groups with more general-purpose themes that foster open-ended discussions (e.g., Leisure). This political content is concentrated in a few users, generating more engagement and further political debate.