Think of the Fediverse as the world and each instance as a different country. Your account on the Fediverse is like your passport, so while you only have one passport belonging to your home country (Your home instance), you can use that passport to travel to different countries around the world.

Lemmy, Mastodon and PixelFed are like the different cultures of the world, while each place has its own way of displaying content, you can travel between them and see them all the same.

Here’s my attempt to explain the fediverse:

Imagine Reddit.com was actually RedditWC.com and RedditEC.com for East and West coast. West coast would have a Seattle community and East coast would have a New York City community. You might be more interested in Seattle so you sign up at RedditWC.com.

Either way, the two sites are constantly sharing all the content created on each so they're a perfect copy of each other so you’ll still be able to participate in the New York City community. This scales to allow a California instance and a Texas instance, etc., each with their own interests and all posts and comments are being synced.

When you load up RedditWC.com, you're seeing everything created on RedditWC.com as well as up to date copies of all content everywhere else you can interact with so it still feels like a complete Reddit.com.

The crux of all of this is each instance has less traffic so the load is spread out, and if instances go offline, other instances can pick up the slack.

I used this analogy in another thread to try and explain what happens when an instance defederates from another: a trade route in the old sailing ship days. People are from different port cities, but each port has a ship that goes to all the other ports, so the people from the ship can trade/interact with the people where they dock.

So with that analogy, given recent events, the port city of Beehaw is one with more restrictive laws about behavior: if you aren’t generally respectful of others, they toss you out. There was a sudden influx at Beehaw of crowded ships from the ports of Lemmy.World and sh.itjust.works, both ports with less restrictive, more wild west attitudes. Beehaw found that their sheriffs were spending all their time tossing people who came from ships with one of those two flags, so they decided not to let those ships dock at their port anymore, or let their ships dock at those ports, for now.