Yes, this is going to be developed further. There is some existing code. We will be publishing a roadmap + how this factors into it, soon!

As the designer / UX guy of Mailpile- to me is how difficult it is to intelligently sort & render the vast array of differing types of email (conversations, lists, receipts, newsletters, notifications, etc...)!

Interesting question. :-)

I think the biggest issue may be the fundamental fact that Mailpile is software that has to run on a computer somewhere - people are getting so accustomed to just getting service for free on the web, that many will balk at having to install an app locally. Folks who value their privacy enough will, but not everyone does.

This will be a problem even assuming we solve the two hard problems and major benefits provided by cloudy solutions: backups and "always on, always available" remote access.

We have not built packages for Linux yet, but we will definitely do so for the 1.0.

Getting the Windows and Mac packages shipped by Beta was a priority so we could get feedback on how they behave and have time to track down issues before the 1.0. The app is already very stable on Linux, there we just need to coordinate with the community to get packages built (and efforts in that direction are already well underway).

Love Mailpile, but for what it's worth, I have the exact same problem. Running mailpile on Windows 8. Entered Bjarni Runar Einarsson's email (since I don't have any friends who encrypt), and it searched for his key indefinitely. So I can't figure out a way to add recipient keys either via contacts.

For all questions security-related, check our Security Roadmap: https://github.com/pagekite/Mailpile/wiki/Security-roadmap

The DIME story is largely "wait and see", but we've reached out to Ladar and the stuff he talked about at DEFCON sounded very promising. We'd love to be one of the first apps to support it.