🌈Is the fediverse confusing you? ELI5: fediverse for dummies🌈
Try thinking of it like the edit: EU. Each instance (lemmy.ml, lemmy.world, kbin, beehaw, etc) is its own separate ‘state’ with its own rules and regulations. When federated, these ‘states’ talk and share content with each other. When defederated, they do not continue to talk between each other. You cannot log into another state/instance using your state/instance’s credentials, but you can see and interact with content from another state/instance.
The beauty of federation is that each instance can choose which they do and do not wish to share content/associate with.
Also, translation for ex-redditors:
subreddit = lemmy community = kbin magazine
kbin/lemmy = reddit clone
mastodon = twitter clone
You can currently connect through any of the above using whichever instance layout you prefer (reddit-like or twitter-like), though given that it’s all very in beta (early on) things will be buggy. ETA: there are, of course, more, but these are the ones I’m most familiar with currently
I hope this helps!