The problem, however, is that most companies still rely on crappy Enterprise services like Microsoft Office. For most people managing identities like this is impossible to do - due to either lack of user-friendly options or due to too high thresholds of necessary IT knowledge.
I mean, we are speaking about having to configure Dovecot and Postfix and similar tools, and I fuck that up regularly. And we are also assuming that they have to be unguessable (you have github@? maybe I should target linkedin@, too, then!) which implies that they have to be random-looking which means they will likely be blocked by registration filters.
Newer projects like Maddy [1] kind of go towards that direction, but are still targeted at developers or sysadmins.
