> You would think it was crazy if your cell phone could call only people with phones on the same network. But we put up with that absurd situation when it comes to instant messaging -- and have for years. Worse, there's little sign of change anytime soon.
The premises to accomplish this are: protocol standardisation, dissemination among users, collaboration between app makers.
> https://en.wikipedia.org/wiki/Comparison_of_instant_messagin...
The decentralised protocols listed are: Bitmessage, Ricochet, Ring and TOX. None of them is widely deployed.
Email is decentralized, that means I can quit Gmail any time I want and use another service. Or even start my own.