We want more control over data that we've created, and more control over data that's about us. I'm not sure either of these concepts align well with "ownership" though. Property and data are concepts that don't mix.

Language nitpicking aside... you subvert the walls of their gardens and aggregate the walled-off data without the walls, so users face a choice not between:

- facebook

- everything else

but instead between

- facebook and everything else

- just facebook

But that approach only works if we can solve the "data I created" problems in a way that doesn't also require us to acknowledges facebook's walls.