Fedive(r)ule

tbh I never quite understood the email analogy because emails are a completely different format, even if the general idea of communication across providers is the same. Comparing it to interoperability between messengers (e.g. accessing Signal groups via Telegram, if that were possible) made it way easier to understand.

To be fair, it's not an insanely simple concept and it'll take people some time to learn it.

To be fair, thanks to Facebook and etc., for many regular emails became way too sophisticated.