You may be new to Lemmy and wondering what it's all about.
Prefer a video? https://www.youtube.com/watch?v=G6xCw9zb5kw
Lemmy is part of the Fediverse, a network of interconnected social media platforms. Lemmy is intended to work like Reddit, but instead of one central site, there is no central site. Instead, there are many different sites (nodes) that talk to each other.
Think of this like email. No one "owns" email. Instead, there are many email servers. Some are large, like Gmail. Some are smaller, like the email server that runs email at your work. And some people run their own email server, just for themselves.
Even though there are many different sites providing email, it does not matter which one you pick. For the most part, any email provider you choose can email any other.
Federated sites work the same way. Lemmy.nz is one site, Lemmy.ml is another. Beehaw.org is yet another. There are many different Lemmy sites, large and small. All these sites have their own users, they have their own communities (subreddits), and they all connect to each other. If you want to view posts on asklemmy on Lemmy.ml, you can subscribe. It doesn't matter which server you signed up to. You can comment on posts, upvote posts, the whole shebang. Regardless of which server you signed up to, you can seamlessly interact with posts, comments, and upvotes across the entire network.
Hopefully this answers more questions than it raises, but really it could go either way. Reply to this post if you have questions (regardless of which server you signed up to).