The Theme Issue invites researchers and scholars to engage with chronometric inequalities and chrononormative concepts, and to interrogate how they shape the experience, assessment, and management of time in an environment of pervasive social platforms. This is important and urgently needed because time use is a critical factor for well-being, mental and physical health, and relationship quality, with algorithmic media being blamed for eating up excessive amounts of screen time, thus inducing depression, anxiety, distress, and weak social connections. Taken together, these contributions open a broader conversation about what might be called the temporal turn in platform and AI studies. They suggest that understanding contemporary digital societies requires asking not only what platforms do, how they govern, or whose interests they serve, but also how they organize time itself. Such a perspective reveals the extent to which contemporary struggles over attention, intimacy, mobility, memory, authenticity, and even mortality are simultaneously struggles over temporal experience. By bringing together studies of interfaces, infrastructures, migration, mobility, intimacy, generative AI, and digital afterlives, this Theme Issue offers a foundation for future research into the politics, practices, and possibilities of time in platformed sociality.