Public institutions are beginning to take an active role in the Fediverse, integrating ActivityPub platforms into their communication and identity ecosystems. This shift brings specific organisational challenges: introducing large and diverse user groups to decentralised networks, aligning institutional identity with the logic of the Social Web, establishing internal responsibilities, and ensuring that data protection and communication standards translate into federated environments. This talk reflects on the experience of introducing a Mastodon instance at the University of Innsbruck, where more than 5,000 staff members can access the Fediverse through the university’s Single Sign-On system. The focus lies on the institutional layer of Fediverse adoption: designing onboarding procedures, coordinating collaboration between departments, developing moderation and communication guidelines, and embedding ActivityPub into established workflows. In addition, the talk highlights what the Social Web ecosystem needs in order to better support institutional participation: more flexible onboarding paths, clearer role and permission models, moderation tools suited to organisational contexts and interfaces that help bridge institutional communication cultures with the norms of decentralised networks. The aim is to outline how institutions can adopt ActivityPub at scale and contribute meaningfully to the Social Web, not only as operators of individual services, but as active partners in shaping open, federated digital spaces.