This paper: http://research.microsoft.com/en-us/um/people/moskal/pdf/beyond-open-source.pdf http://research.microsoft.com/en-us/um/people/moskal/pdf/bey... desc

This paper: http://research.microsoft.com/en-us/um/people/moskal/pdf/beyond-open-source.pdf http://research.microsoft.com/en-us/um/people/moskal/pdf/bey... describes the basic idea behind integrating an IDE, GitHub-like collaboration, and an app store. The main thing about the interface it's that it's touch-optimized and has this unique semi-structured editor, where the expressions (as opposed to statements) are edited token by token, and not as a tree. This was proven to work better on touch-devices.