I've been explaining it as countries/international travel. Lemmy is a country, Mastodon is a country, you can travel freely between them but you need a passport. Each service has it's own government whose rules you have to abide. Lemmy instances are like states (or provinces or what have you), where you can just... freely travel between them. Each instance has it's own local government whose rules you have to abide. Communities are like cities/towns, with their own small local government whose rules you have to abide... etc, etc.
I’ve been using the email metaphor to explain what it is and then sending them to sh.itjust.works
I've been explaining it as countries/international travel. Lemmy is a country, Mastodon is a country, you can travel freely between them but you need a passport. Each service has it's own government whose rules you have to abide. Lemmy instances are like states (or provinces or what have you), where you can just... freely travel between them. Each instance has it's own local government whose rules you have to abide. Communities are like cities/towns, with their own small local government whose rules you have to abide... etc, etc.
Nice way to explain it
Such a great instance name
It definitely lives up to its name as well