I'm not sure, is part of the fediverse so we can interact (in the same way that mastodon users can read and reply to lemmy posts), but it's a different project with different code. Communities are called Magazines there, and there's also a microblogging functionality. I've lurked a bit kbin.social, but I won't create an account if I can use this one.
It also appears to not be fully federated or something.