1) The service is free, so if you're data gets lost, you're out of luck.
2) The government just has to ask nicely to look at the data without a court order.
3) Your data becomes the property of the 3rd party whose service you are using.
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) The service is free, so if you're data gets lost, you're out of luck.
2) The government just has to ask nicely to look at the data without a court order.
3) Your data becomes the property of the 3rd party whose service you are using.