1) Your data is stored, encrypted by you, in the cloud
2) In a standards-based service which you pay for
3) And federated to other services by you
Mozilla Weave was an instance of a narrow application of this:
http://mozillalabs.com/blog/2007/12/introducing-weave/
There is still the issue that once you grant access to a third party you can't revoke it, but that's unsolvable through technical means in somewhat the same way DRM is unsolvable.
1) Your data is stored, encrypted by you, in the cloud
2) In a standards-based service which you pay for
3) And federated to other services by you
Mozilla Weave was an instance of a narrow application of this:
http://mozillalabs.com/blog/2007/12/introducing-weave/
There is still the issue that once you grant access to a third party you can't revoke it, but that's unsolvable through technical means in somewhat the same way DRM is unsolvable.