"You can have an email account on any number of servers, and you can send email anywhere, no matter where your account is."
"You can have a Mastodon account on whichever server you like, and you can follow people anywhere, no matter where your account is."
It just seems like a paradigm people already understand that might be more welcoming.
If you don't like your email provider, just change to a different one...
Oh yeah. And you'll lose all your previous emails. But we won't mention that.
It has a built in mail forwarding process.
But it's an analogy intended to help with the server selection process; I don't think it has to be perfect.
"You can sign up with one of these main instances and follow people no matter where their account is. If you find make a lot of friends in a specific corner of the Fediverse, or just want to switch to another instance, you can do so whenever you want."