[anderspitman]

The ability to send messages is perhaps the less interesting role of email. I think maybe the real value comes from providing globally unique, federated identities. It's not perfect, but it's pretty dang good.

If for no other reason, this is why no closed system will never supplant email. Even the biggest walled gardens like GOOG and FB bow to the power of email identities in the end, as the preferred (maybe even only) way to recover an account.