Plebbit is a selfhosted, opensource, nonprofit social media protocol, this project was created due to wanting to give control of communication and data back to the people.
Plebbit only hosts text. Images from google and other sites can be linked/embedded in posts. This fixes the issue of hosting any nefarious content.
ENS domain are used to name communities.
Plebbit currently offers different UIs. Old reddit and new reddit, 4chanw, andhave a Blog. Plebbit intend to have an app, internet archive, wiki and twitter and Lemmy. Choice is important. The backend/communities are shared across clients.
Actually, a lot of people refer to the internet as federated, because most all of it is very decentralized, and independently managed.
Take IP routes... The BGP table is a giant exercise in federation. Any transit provide can blackhole your traffic, or just refuse to accept the announcements (ie, a lot of places reject North Korean BGP announcements, for example).
DNS is another example of a federated system, a number of countries operate the root servers, who merely hold pointers to where to get answers for a TLD, which in turns just provides answers on who can provide answers for a domain.
You can even create your own TLDs, and use them!
Its a giant, federated system. The apps sitting on top of it are not so much anymore.