Here's my attempt at making it as simple as possible. (Sorry to anyone who has seen me repost this in several different communities, just trying to make it easier for people to engage and this seems to have good feedback)

The Fediverse

• The Fediverse -- Federation + Universe -- is a space on the internet that hosts several social media-like platforms. Lemmy is like Reddit, Mastodon is like Twitter, PeerTube is like YouTube, etc.

• The main difference -- in terms of ownership and influence -- is that these platforms aren't owned by a single entity in the same way Google owns YouTube, Elon Musk with Twitter, Meta with Facebook, etc. In contrast, the Fediverse and its platforms are decentralized meaning no one wholly owns it and a person can't just make a decision for the entire Fediverse/platform.

• As a relevant example, no one can just arbitrarily decide to make you pay $20 million per year for accessing a platform's backend stuff. The Fediverse avoids the advertising, algorithms, and other unpleasantries that plague many social networks.

• As well, different platforms within the Fediverse can communicate with each other, like how a Gmail user can email a Yahoo Mail user. Reddit, Twitter, and YouTube can't do that.

Lemmy

• Going back to trying to ELI5 Lemmy... Lemmy the platform, within the Fediverse, is one planet. Like planet Earth in the universe

• “Instances” like lemmy.world, lemmy.ml, beehaw.org, etc. are like the different countries on Earth

• When someone signs up, the user picks one instance to be a part of, like how an Earthling becomes a citizen of a country

• If you register at lemmy.world, that means your home instance / “home country” is lemmy.world, but you can “travel” to lemmy.ml, another instance / “country”, to check out and subscribe to their community

• When you subscribe to a different instance that’s not your home instance, you can still participate in their content, and other people will be able to see which instance / “country” you’re from

• Each instance can have its own version of the same community / “subreddit”, so you can have a c/Memes in your home instance that is different from a c/Memes in another instance. But you can subscribe to both separately

• c/[community name] is the naming convention used here I think like r/[subreddit name] on Reddit. If talking about a community in a different instance, it's c/[community name]@[instance name] so like c/memes@lemmy.ml

Someone please correct any of this if any of it is wrong, I’ll happily edit

Imagine several people building a sand castle at the beach. Anyone can join, just start building your own little tower and then connect it to the main castle (this is instances explained). You can also invite anyone to work on your specific part of the castle and build the tower with you (users joining an instance).

Answer: there are probably better people to explain Lemmy specifically than me, but I went down the Fediverse rabbit trail when Mastodon was being talked about as a Twitter alternative so I think I can get the basics down.

Fediverse is a collection of servers which all agree to use the same communication protocols. This allows them to communicate with each other even when they aren't run by the same company/organization. You can't see someone's Facebook post on Reddit or vice versa (screenshot apocalypse notwithstanding) because Facebook and Reddit haven't agreed for their sites to be able to communicate with each other. The Fediverse is designed to allow different people hosting their own Fediverse servers to be able to interact with each other.

Lemmy is (to the best of my knowledge) a specific subset of the Fediverse designed to replicate the same kind of interactions seen on Reddit (communities => subreddits, post/comments, upvotes/downvotes, etc). So anybody can create their own Lemmy instance, and interact freely with all of the other Lemmy instances.

TECHNICALLY a Lemmy instance can even interact with other Fediverse instances not using Lemmy (Mastodon for example). But I'm not quite sure how that works given that a Mastodon toot doesn't have the same structure as a Lemmy post

It's a version of Reddit built on the Fediverse.

The Fediverse is a system that combines a centralised collection of content with an early-internet free-for-all for content delivery. That's good because it feels like social media (in theory) but nobody actually owns it.

Think of email as people sending letters over the phone. When it first came out, mail carriers only took their specific-sized paper, which couldn't fit into mailboxes provided by other carriers. People could only mail each other if they used the same carrier. For example, kids wanted to send letters to grandmas, but the grandmas used different carriers. Eventually, some carriers got together and decided to use the same size of paper and mailbox size. The standardization became the email protocol.

However, with the new ease of sending letters, some mean people started sending messages to the grandmas, so grandmas stopped allowing all the carriers to deliver to them. This is how ban lists were made.

Grandmas can be very different, and each has their own things they are okay with. Eventually, this led to many bans making it hard to keep up except for the largest carriers that could hire staff to ensure compliance. They bought out the smaller carriers as more people switched to them. This is called centralization.

Some grandmas thought it would be neat to find and share recipes together. They sent their collections to recipe magazines and asked the magazines to send the completed magazines back to themselves, the other grandmas, and their grandkids. These became the first media forums, blogs, and websites. Eventually, people wanted to get their blogs about different topics all in one place. This became social media.

It was really messy at first because the magazines/websites created were in the order that the stories were received. They could be about anything, and some of the stories were from that yucky kid in class that talks about bugs and poop all day. To solve that, they started voting on what topics were the best and only showing the good ones to everyone but allowing those that really wanted to hear about bugs and poop still read and talk about that. This became link aggregation.

The rules for how that voting worked were decided by the website owners. Sometimes they would cheat to get their stories put to the top, for example, their choice of who Superman or Batman was the best superhero. People started wondering why they had to listen to those people, so they started making their own websites. All these small splits ended up with the main website everyone went to and mostly empty websites about whatever topic the small website wanted to discuss. Since that didn't solve the situation, they came up with the idea that maybe the small websites should talk to each other, and as long as they didn't talk about the one issue, they split from the big website. They could all stop being on the big website. This was called federation.

Lemmy is federation for link aggregators.

Edit: formatting / grammar fixes

I'm mad at Reddit so I'm going to create my own reddit that works the exact same way. You can post, make subreddits, like and comment, everything. The only problem is I only have a userbase of 10 people. There's kind of a catch 22 with maintaining a userbase on social media: if I don't have enough users, no one will want to join, so I'll have even fewer users.

One thing that can help is the fact that you have your own separate reddit clone that also has 10 users. We can work together and make our websites compatible with each other and speak the same language. Now my users can see your subreddits and posts and interact with your users like there's nothing separating them. A community emerges of 20 people that transcends the boundaries of the individual websites.

Now say we take our code, call it Lemmy, and post it for free on the internet so anyone can copy it and make their own reddit clone to add to the network. These are all separate websites, called instances, but since they speak the same language (ActivityPub), all the users can interact with each other.

email but with social media

You know what Reddit is, right? It’s a website where you can join different groups about things you like, such as animals, games, or books. You can also post links or messages in those groups, and other people can vote and comment on them. Lemmy is a lot like Reddit, but it has some differences. One difference is that Lemmy is not run by one big company, but by many small servers that anyone can set up. These servers are like little islands that can talk to each other. Another difference is that Lemmy is more respectful of your privacy and freedom. It does not track you or show you ads. It also lets you choose what kind of content you want to see, and does not censor or ban you for having different opinions. Lemmy is a new and growing website that wants to be a better alternative to Reddit. You can also make new friends and have fun discussions with them.

Think of an email address. Accessing a community is like accessing an email address (that's why communities have handles @ a server.

So unlike Reddit where you could have r/memes in the Fediverse you can have memes@lemmy.world or memes@lemmy.ml each host can host a bunch of communities and a bunch of users and we all connect to one another in a similar way that email works.

The plus side of this is that no single company has all the power like a walled garden, rather the whole system functions in a decentralised manner. It is also run open source by a community of developers. So while the whole system works in a very similar way to Reddit, you cant just search for the official memes community, rather you can subscribe to many, some may be large and some may be small and niche. Hopefully the downsides of this will get ironed out, organising communities into super communities or sorting by tag or something, but on the bright side, being open source and decentralised, development of Lemmy will likely proceed at a rapid pace and soon catch up and overtake corporate sites in useability, as they increasingly look to stifle useability and freedom for profit.