I was struggling to wrap my head around how federated social media works until I realized that email has basically been doing the same thing for 30 years. Different email servers are like instances of a federated network. You can send emails to people from within a single server or you can send emails to people on any other mail server. Your email address is a username followed by an ‘@’ and the server address, just like on Lemmy. Email is a decentralized service I’ve been using the whole time!
This is… either simplified to be confusing or a big misunderstanding of kind of everything. Google bought DejaNews an online Usenet text archive. Usenet still exists right now, and there are still at least 5 or more major Usenet server providers you could sign up with today, but most charge for access.