I don't get it - why is this cool? Isn't "mail" one of those outdated meatspace idioms we can finally allow to die?
i'd have serious doubts about someone wanting to correspond about business matters via twitter, facebook, etc.
so i'd say that, no, mail is not something outdated and should die - just another form of communication that has it's place.
It's at least 15 years old and faded out with the rest of the "cyberpunk" genre.
It's just a handy word to refer to stuff that's not online.