So, Lemmy (and by extension Beehaw) can be federated. (Although the instance admins can make a non-federated instance, but it’s not really relevant in this case.)
This means that there’s actually multiple Lemmy “worlds” living next to each other, and they can interact between each other. You can post in your world, and people from other worlds can come, read what you wrote and leave a comment.
Think of it like email, as it’s a great example to explain federated and decentralized software:
- You have a GMail account,
- You receive mails from other people on GMail: no problem there, it’s something internal to the service, you can read and reply to the mail,
- You receive a mail from someone using a Microsoft Mail account (live.com, or whatever)… no problems there either, you will receive the mail, be able to read it and reply to it,
- But, if you want to reply to it… you’re not going to sign in to live.com, right? You’re going to use your mail.google.com account to do so.
Lemmy works the same. You received a comment from someone on lemmy.ca, which is pretty cool, right? If you want to reply, you’ll have to do it through your beehaw.org account - because that’s where your “identity” lives. Beehaw certifies your identity, and your device can use this certification to reply to that person on Lemmy Canada - but this means that you still need to go through Beehaw to reply to the Lemmy Canada person.
And if you follow the link to your thread on beehaw.org, you’ll also be able to see that person’s comment… and be able to reply to it! To summarize it: you don’t need to have an account on other instances to interact with people on other instances. Just like you don’t need to have an account on Hotmail to interact with people there if you have a Gmail. You just login to your Gmail and do it from there. That’s federation/decentralization.
Hope that helped - the web has worked with centralized services for almost two decades now, which can make things confusing. But decentralization is really not that bad once you get the gist of it. And it’s a much more elegant technical solution as well.