In this chapter, we discuss the potential and challenges of digital communication in advocacy and social mobilization for public health. Digitalization has significantly impacted the flow of information, both positive and negative, emphasizing the need for evidence-based communication to counter misinformation and speculation. Using the COVID-19 infodemic as an example, we highlight how social mobilization through social networks can influence public health. Digital communication poses both increased opportunities for advocacy and social mobilization and increased risks through complex digital environments and disparities in digital health literacy among different population groups. In order to be effective for advocacy and social mobilization, digital health communication needs to be timely, transparent, accurate, and appropriate. We use three examples to exemplify the potential and risks of digital communication for social mobilization and advocacy: (1) the German Competence Network Public Health COVID-19, which utilized digital technology to compile and disseminate evidence to policymakers, (2) the adverse impact of misinformation and the strategies employed by “super sharers” on social media to spread misleading health-related information, and (3) how digital communication enables grassroots digital tactics in planetary health activism. We highlight important processes and preconditions to find effective solutions to communicate and inform efficiently and independently in the digital space while addressing the dynamics of the attention economy and the influence of major digital corporations.