@carhauler @Gargron that's a bit of a misconception. You typically only need an account on one instance. Then, the instance you are on can talk to other instances.
For example, I am not on mastodon.social, or using the Mastodon software at all. Instead I host another federated software called Pleroma. Via federation instances of different software send events to each other and receive events. So I can see and respond to you, and you can see and respond to me even though we are on different sites.