That didn't take long. Yesterday I shared my Mastodon address as an alternative to following a ghost on Twitter. Within hours I got a link (by email) explaining some weirdness connecting with people I knew on other instances of Mastodon.
In what can only be called a "double turns-out", Mastodon instances can be changed in ways to not be part of the federated group. So, I guess centralized might be the only way to have a unified communication channel. Within two days I've moved from one Mastodon instance to another. I've noticed that this is somewhat common.
I moved to @firstname.lastname@example.org
Here's an invite link.