Mobile instant messaging services (MIMs) are important gateways to news exposure and political conversations. Nevertheless, we still know little about the specific uses and consequences of using messaging apps on other aspects of democratic citizenship. This is especially true in Latin American countries, where usage of MIMs is more widespread than any other social media. Using a two-wave panel survey conducted in the context of the 2017 Chilean elections, this study examines the information sharing practices of WhatsApp users, comparing the antecedents and effects of the spread of personal (e.g., family, work) and public affairs content (e.g., news, political messages). Findings show that sharing on WhatsApp was rather equal across social groups, and that it could exert a significant influence on learning about politics and issues in the news as well as on protesting and other political behaviors. We discuss possible explanations, limitations, and significance of these results for digital journalism research and practice.