When Hotmail appeared I signed up like an eager beaver to mail silly notes to my friends. Then came Yahoo! Mail and I moved on there. It did not help that Microsoft had bought Hotmail and I thought now it would stop being free etc.
About three years back I signed onto Gmail and became a fan. I hardly use Yahoo! anymore since it does not offer half the features that Gmail has.
Nowadays, when somebody gives me his or her email account, I quickly size them up in the email hierarchy. If it is an office account, they are higher up. Gmail of course means that we are equals. Yahoo means the person is about few years behind on internet literacy. Hotmail means the person is a dinosaur as far as I am concerned. So much so that I got my parents to open their accounts on Gmail. Never mind they still use it like Hotmail.
Do you have an email hierarchy?