So clicking on an instance’s instance list I can see all the linked instances and all the blocked instances.
Are these all instances that exist? What happens if a single person creates an instance? Is it then automatically “linked” or “blocked” or does it just exist “unlinked”. If it exists “unlinked” then what is the difference between “unlinked” and blocked". And how could I get my instance linked if I create a new one?
An instance is not federated with another until the first link is initiated manually. After that, they can talk to each other.
This is why if you are browsing a curated list of instances/communities on some website, and then go to search for them on your current instance, sometimes they don’t show up, and you have to paste the full link in the search bar and wait for it to “find” it. You are initiating its federation.
So, no, this is not all instances. Some are still yet to be discovered by yours.
This “unlinked” state is different from being blocked, because a blocked instance is actively forbidden from being federated with your server. It can’t talk to you even if it wants to, and you can’t talk to them either. A total disconnect.
If you make your own instance you’ll probably have to manually connect to some others to start with. Following people helps, because it adds any servers that they follow too.
If you create a new instance nobody knows about you until you start interacting with other instances by for example subscribing to a community. This builds the link.
Check out official documentation it does a good job on explaining it.
