The COVID-19 pandemic has highlighted the challenge of conveying and communicating complexity and uncertainty to the public, also given the increasing central role of the Internet and social media. Designed to maximise users' presence on the platform and to deliver targeted advertising, social media transformed the information landscape and have rapidly become the main information sources for many of their users. Information spreads faster and farther online, in a flow-through system where users have immediate access to unlimited content. This may facilitate the proliferation of mis- and dis-information, generating chaos, and limiting access to correct information. In this talk, I will provide an overview of how online social dynamics and behavioural patterns can be investigated in a quantitative and interdisciplinary way. Moreover, I will discuss how data-driven insights can be used to design tailored policy recommendations.