> It already happened for personal correspondence (facebook) and I'm sure at some point it'll happen for work correspondence too.
I don't know the numbers but I'm part of the population that never used Facebook, so I'm unconvinced you can generalize like that.
> Put simply, in a world where clients are all free and the identifier of choice is the phone number, federation doesn't add much value.
I didn't really understand Moxie's arguments, but he may know more due to the projects he's involved in.
But how is interoperability achieved? The beauty of HTTP, NNTP and SMTP are that you're not bound to one (or maybe two) client experiences or server implementations. I don't understand the desire to leave achievements like that on the floor just for temporary comfort. It's a slippery slope and will lead us into a long time of silo'd communication.
To me the current proposals look like if I had to use 4 different post offices depending on whom I want to send a package to. There's a reason addresses are universal.