So you think this is being pitched as a form of DRM? Somehow preventing content from being copied/stolen?
Personally, i take "data ownership" as a hosting issue. Where it originates from, where it lives. Not specifically protecting anyone from copying it. Eg, Facebook is a sort of vendor lock-in. You end up entrenched in their platform, because your content cannot be swapped to, so, Google+ with ease. If you had true ownership of the data, you could theoretically swap as your desires dictate.
If your idea of ownership was true (assuming i'm understanding you correctly!), then that would mean Twitter, Facebook, etc don't actually own your data either. Because you can copy your Facebook data. There is no lockin with Facebook, and our problem with ownership is that someone else in your friends-list can copy/steal your data?
