Building on the theoretical and empirical discussions developed throughout this book, this chapter synthesizes how online platforms are transforming the communicative dimensions of international relations. Far from being neutral infrastructures, platforms act as geopolitical environments. By intertwining the logics of conflict and diplomacy, they redefine who can speak, what can be seen, and how narratives circulate. The chapter revisits the book’s key arguments: platforms as sociotechnical assemblages where market, institutional, and everyday forces converge; as actors that amplify wars through algorithmic visibility; and as arenas where diplomacy becomes performative and entangled with entertainment logic. It also identifies three emerging research directions: transformations of agency and participation; the interplay between space, materiality, and mediation; and the redefinition of the diplomatic public. As generative AI and platform governance increasingly shape global communication, international affairs must confront new forms of human–machine agency, where the infrastructures of visibility themselves become critical sites of power, negotiation, and contestation.