It is just simply a decentralized social network, you register and treat it like as if it is any other social network.

This guide from the people who run lemmy.ca is a good starting point.

Like email but in the style of platforms like reddit, twitter, YouTube, Facebook, etc. There is no one site to create an email yet you can send an email to anyone no matter who their provider is. The fediverse aims to do that but with other platforms.

Hi!

Since you’re on Lemmy, I’ll explain the part of the fediverse that I know best. The best way I can articulate it based on what I know is this… it’s a bunch of different sites, using the same software, known as Lemmy. Each site using the Lemmy software is called an instance, and these instances are able to correspond in a way that is pretty seamless as if it’s all one big site! Although you never actually leave your native instance, it doesn’t feel that way because when you post to an instance that isn’t your native one, it’s like sending a request to that instance to push your post forward. In no time, your post appears on the remote instance!

One of the best things about this is each instance is independently operated, so you don’t have to worry about a rogue admin making unfavourable changes. For instance (hehe) I’m on the lemm.ee instance, but I’m posting to Ask [email protected] via this page! lemm.ee/post/62441272

I suppose you are on lemmy. Lemmy is kind of the reddit of the fediverse. Imagine that now everyone can create their own reddit server with blackjack and hookers. That is the server you are on, someone decided to create a server for the world. But now I am on another server with different owners, rules and mods (basically blackjack and different hookers). I can interact with you on your server and you can interact with me on my server because our servers are federated.

Now imagine that you can do this for every social media. Reddit, X(itter), Instagram, YouTube, Tiktok, WhatsApp. Everything is available in the fediverse (with more or less issues depending on what you are looking for).

The fediverse is a diverse social network that is distributed across multiple platforms.

Going from the basis to the specific services:

• The ActivityPub protocol defines a protocol - data structures and forms of data transfers
• The Fediverse is a collection of different social networks and services hosting these social networks that can and do connect and communicate with each other
• Various social platform software like Lemmy, Pixelfed, Mastodon implement (“speak”) ActivityPub and are part of the Fediverse
• Anyone willing can run (host) their own instance of these, by downloading and running them
• The platforms have difference interfaces and capabilities, but in one form or another, users can connect and use other platforms despite them being “different”

For example:

Lemmy is a social platform like Reddit, but anyone can host their own instance. Users can make accounts and create communities on different instances. Users can then follow and interact with communities from other instances.

For example, my account is on feddit.org, but I am posting this comment to [email protected]. Because I follow the community, feddit.org fetches and copies the data from that community, and any activity from either side gets communicated to the other. As a result, you on lemmy.world and me on feddit.org can both see and interact with the same community.

Mastodon is a social platform like Twitter. Someone may have their account on mastodon.social, which is one such instance running Mastodon. Despite being a different use-case and interface, they can follow, read, and post to Lemmy communities.

I tried replying to this comment from mastodon.social. I was able to view this post and this comment. I don’t know if the comment will show up or not; maybe lemmy.world blocks mastodon.social comments.

The Fediverse is the collection of compatible services and networks that can speak and connect to each other.

Various servers using various software that can communicate with each other.