I've been thinking of trying my hand at an app that is nothing more than a thin layer on top of email. It would receive email, occasionally send email, but not

I've been thinking of trying my hand at an app that is nothing more than a thin layer on top of email. It would receive email, occasionally send email, but not really do anything else with the user's actual email account. I'm not very familiar with email other than as a user, so my question is: how easy would this be? Ideally I want to avoid mucking about too much with the email protocols or store a person's entire collection of emails...