When you set up a lemmy instance, it has no idea other instances exist. It’s like throwing you into a web browser with no search engine. You don’t immediately see every single website, you have someone tell you about a cool website you found, and then you type it into the address bar, and save it.
It’s kind of the same thing with Lemmy instances and communities. Once a user types this syntax into the search prompt:
!community@instance.com
It will try and contact instance.com for that community. If it exists, the user can subscribe and the instances will now receive and send new posts to each other.
an ELI5:
When you set up a lemmy instance, it has no idea other instances exist. It’s like throwing you into a web browser with no search engine. You don’t immediately see every single website, you have someone tell you about a cool website you found, and then you type it into the address bar, and save it.
It’s kind of the same thing with Lemmy instances and communities. Once a user types this syntax into the search prompt:
!community@instance.com
It will try and contact instance.com for that community. If it exists, the user can subscribe and the instances will now receive and send new posts to each other.
Mastodon has this issue too, fwiw.
I wouldn’t say it’s an issue. Great way to make new instances not be flooded with 500000 submissions per second.