Principles

TODO: elaborate. This is just a quick sketch.

Disk is cheap and getting cheaper. No need to delete in general.
Put the user in control. Own your data.
Privacy and paranoia
Decentralization is important, but..
End users won't be dorks. Must also be possible to be easy, hosted.
Content-Addressability has so many great properties (validation, cachability, etc). Use it as much as possible.
Redundancy and over-explicitness is fine. Compression will help. Redundancy and over-explicitness will be convenient for future digital archeologists, too.