I don’t know where exactly to post this question but there are two communities on two different instances. Are those same?
If not there can be n number of such communities on any instance how to get saturated content if them all? Is there better alternative than lemmy?
I agree. It also works well for small differences between communities. For example a Lemmy.world gaming community might not allow discussion of piracy and it is allowed here. This instance also has rules against NSFW content and another instance might not.
The ideological diversity the fediverse allows is one of the coolest parts about it. There are instance admins, but there’s no such thing as a single fediverse admin so everyone can have their little corner of the fediverse and it has its own attributes.
So throwing out a hypothetical here. I am going to migrate a sub from reddit where I was basically the only person creating the content. How would I keep someone else from picking the same username as me on a different instance, and then copying my exact posts after I post them on my instance? The content I put up on reddit solely belonged to me, but I do have a little concern about the scenario that I am posing.
On the desktop version of Lemmy I believe it lists the instance along with the username.
If you are worried about users using an app like Jerboa not being able to tell the difference you could rely on things like a unique profile picture or PGP signatures. It all really depends on your threat model.
It would be a lot of work to do anything more than cross post your content.