Facebook expanded until it could send and receive facebook walled garden mail (fb messages).
iOS has iMessage.
Instagram and tinder and snapchat all support the basic concept of “mail”.
In fact, I wonder how many apps I have installed that don’t have some concept of an “inbox” or “messages”. Taskrabbit, Uber, GrubHub - all do “mail” in the modern, unfederated sense of the term.
(email started out unfederated, then we got uucp and smtp, now we are back to unfederated, centralized messaging.)
iOS has iMessage.
Instagram and tinder and snapchat all support the basic concept of “mail”.
In fact, I wonder how many apps I have installed that don’t have some concept of an “inbox” or “messages”. Taskrabbit, Uber, GrubHub - all do “mail” in the modern, unfederated sense of the term.
(email started out unfederated, then we got uucp and smtp, now we are back to unfederated, centralized messaging.)