I don't think it's quite so gloomy. A lot of cool add-on functionality relies on semantic markup in the email itself [0]. These are open standards by necessity

I don't think it's quite so gloomy. A lot of cool add-on functionality relies on semantic markup in the email itself [0]. These are open standards by necessity -- any email provider can add support for them. For example, here's the standard for flight reservations [1]. I'm not sure how widely adopted they are, but Microsoft supports at least event discovery [2]. [0] https://developers.google.com/gmail/markup/ https://developers.google.com/gmail/markup/ [1] http://schema.org/FlightReservation http://schema.org/FlightReservation [2] https://support.office.com/en-us/article/Automatically-add-travel-and-package-delivery-events-to-your-calendar-32e5cf0c-3e65-4870-9ff9-df3683d3fc97 https://support.office.com/en-us/article/Automatically-add-t... edit: formatting