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).

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.

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

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.