Email is just a stream of information. It can be badly managed and annoying or well managed and useful. The one massive advantage over a random social network

Email is just a stream of information. It can be badly managed and annoying or well managed and useful. The one massive advantage over a random social network is that absolutely everyone has it and can use it. It neatly sidesteps all the authentication/sign up/access problems which make other services difficult to use between large organisations. It may sometimes fail as an app, but it is hugely successful and useful as a protocol.