Email is only ONE, albeit a fundamental one, of the many services that need to be managed in the way Mailpile proposes. I proposed at the end of last year one way to create a unified solution to the general problem, in this post: http://stop.zona-m.net/2013/01/the-alternatives-to-apple-facebook-c-already-exist-shall-we-package-them/
All feedback is very welcome of course.