spwyll

I’m good at quite a few things. Doesn’t help…

Always the correct reaction to hearing something you disagree with. Or perhaps I’m just less autistic than the tests say… /s

This is a case where the email analogy is perfect. In your question you create an address “email@gmail.com” and someone else creates an address “email@yahoo.com.” Both accounts will be able to send email to each other and anyone else can send or receive email to/from both addresses. But email sent to “email@gmail.com” will not show up at “email@yahoo.com” nor vice versa.