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!
I was relying heavily on the quotes around “bought”. A large amount of Usenet had consolidated under Deja which went to Google. While there is still some remnants around. What it was before is no where near the same as it is now.