Here is my simple understanding of things: (please correct me if I’m wrong)
lemmy.world is an instance of lemmy and it is connected to most other instances of lemmy.
Instances that are connected can see post and comments of each other.
However the host of a niche instance can adjust the connection, e.g. make the instance read-only for other instances. General purpose instances (like lemmy.world) usually don’t do that.
tldr: A lemmy instance is like a reddit. So there are many “reddits” now and most of them talk to each other creating one super reddit a.k.a. lemmy.
Here is my simple understanding of things: (please correct me if I’m wrong)
lemmy.world is an instance of lemmy and it is connected to most other instances of lemmy.
Instances that are connected can see post and comments of each other.
However the host of a niche instance can adjust the connection, e.g. make the instance read-only for other instances. General purpose instances (like lemmy.world) usually don’t do that.
tldr: A lemmy instance is like a reddit. So there are many “reddits” now and most of them talk to each other creating one super reddit a.k.a. lemmy.