I think your last paragraph just described email. There are so many apps that are built on top of email and it's only very recently that pseudo-standards* of co

I think your last paragraph just described email. There are so many apps that are built on top of email and it's only very recently that pseudo-standards* of communication (Slack, Facebook Messenger) have sprung up as an alternative upon which you can build your apps with reasonable ubiquity. * The commercial nature of the internet is likely to produce more pseudo-standards than actual standards for us to build on going forward. These are platforms that everyone now takes as baselines. Stripe in payments. Shopify in e-commerce. And so on.