Basically yes, same idea. You signed up for a server, lemmy.world from the looks of it, and This Server talks to other servers running the same or similar software. Servers host communities, sometimes redundantly. If a server sucks, your server can be Federate from it so the posts don't propagate. You posted them like subreddits you comment, everything more or less works the way you expect. Reddit used to be cool but it went down the drain. Said to see it go but we can recreate everything that was good about it. I've been using Lemmy for a while and if you want to discuss headlines and Tech you basically don't need Reddit anymore, this place fills that need. For some of the more Niche stuff there aren't really active communities yet, which you can fix if you like posting stuff. There's assholes sometimes but it's generally not a problem in my experience. It's just the standard Internet troll problem not the turbo shit you get from corporate crap these days.