Online social network services (OSNSs), such as Facebook Messenger, Email, Twitter, SMS, etc., have become an integral part of our daily lives. At the same time, the aggressive market competition has led to the emergence of multiple competing siloed OSNSs that cannot interoperate. As a consequence, people face the burden of creating and managing multiple OSNS accounts and learning how to use them, to stay connected. USNB provides interoperability between heterogeneous OSNSs, allowing people to use their favorite one to communicate. In our approach, social entities can be humans or systems. They can create a profile in USNB and link it with their OSNSs identities. Social entities can also choose the OSNS identity they want to use when contacted through USNB or specify one or more OSNS identities for message reception concerning specific events or senders. Personae are USNB entities interacting with users within concrete OSNSs, achieving interoperability between heterogeneous OSNSs. New personae can be developed, registered with USNB, discovered, and used to include additional OSNSs. USNB is designed to be as less intrusive as possible. It does not ask users their credentials nor any kind of authorization concerning their OSNS accounts.
USNB is developed with the support of the EIT Digital CivicBudget activity.