Fediverse
The Fediverse (a portmanteau of “federation” and “universe”) is an ensemble of federated (i.e. interconnected) servers that are used for web publishing (i.e. social networking, microblogging, blogging, or websites) and file hosting, but which, while independently hosted, can communicate with each other. On different servers (instances), users can create so-called identities. These identities are able to communicate over the boundaries of the instances because the software running on the servers supports one or more communication protocols which follow an open standard, most notably ActivtyPub.