They’re both Lemmy instances, and that makes them both “like reddit”.
As a user, you can create an account on either.
As a mod, you can create an community (aka subreddit) on either.
When a user on world subscribes to a community on ml, ml starts copying new posts to world so users there can read them.
When a user on world comments or posts to a community on ml, it gets copied the other way.
Federation works with more than 2 instances, if a user on instance-a posts on a community on ml, that post gets copied to ml, which then further copies it to all subscribing instances.
All of which is to say… many Lemmy instances federate together to make a super-reddit. Each individual instance participates, and you can (mostly) make an account on any instance and interact with users and communities on other instance.
They’re different federated instances.
worldsubscribes to a community onml,mlstarts copying new posts toworldso users there can read them.worldcomments or posts to a community onml, it gets copied the other way.instance-aposts on a community onml, that post gets copied toml, which then further copies it to all subscribing instances.All of which is to say… many Lemmy instances federate together to make a super-reddit. Each individual instance participates, and you can (mostly) make an account on any instance and interact with users and communities on other instance.