For messaging i think early skype had it sorted more or less , decentralised - widely used and intuitive identity. If it had been allowed to evolve identity

For messaging i think early skype had it sorted more or less , decentralised - widely used and intuitive identity. If it had been allowed to evolve identity maybe like email(matrix or even bsky) got federated with custom servers/identities and handles that could still interoperate, would be nice. Instead MS bought it and ran it into the ground.