While it might seem that way to someone who is using lemmy or mastodon or any of the other fediverse apps. To a new user it will be overwhelming and almost everyone has the same first question “Do I have to create an account on all instances?” To which a lot of people familiar with the fediverse would say “No” but the caveat being you might have to create an account on more than one instance coz maybe your current instance was blocked by the other instance that you might be trying to access. It took me a day of reading exploring and understanding to get this far. So while the mail example maybe pretty simple and easy to understand it’s still not exactly as simple as that. A better example would be if you have a Twitter account you can access Gmail, YouTube, Instagram and Facebook with a single account if the other apps (instances) allow it. Also with that said there can be multiple variants of the Twitter app (instance), say Twitter 1 , Twitter 2 , Twitter 3 each with their own Communities and rules. They may or may not be able to communicate with each other depending on the moderation and community rules. So you see how even the simple examples slowly start to get complex.