This chapter introduces the concept of social participation and analyzes its recent transformations in a postdigital–biodigital reality. It explores the main sources of biodigital (in)equality and links them to the nature of biodigital communication. Drawing firstly on the work of Kate O’Riordan, the chapter argues that traditional communication based on an exchange of information is significantly different from emerging forms of biodigital communication and identifies the regulation of biodigital communication as the key question of social participation in a postdigital–biodigital age. The discussion then addresses in detail the complex power relationships that emerge in this age, the varying levels of participation that different individuals enjoy, and associated political rationalities. The chapter then explores aspects of postdigital–biodigital policymaking using the case of education and drawing on Human Data Interaction (HDI) theory.