Actually Facebook doesn't need to co-own it. If the user uploads a Facebook dump with UIDs then that relationship info is only useful if someone with a corresponding UID provides more data. But once it leaves Facebook it's free and owned by the user. What I meant is that if you don't like Facebook's UID system then you should build your own social network from scratch, otherwise these pre-built relationship data is still really valuable.
Also the UID is the relationship data. You do get that. No need to go out and dump emails which you didn't build. If you do get that info facebook would have to GIVE that to you.
> If you don't want me to have your email address I'm not your friend.
That actually depends on how Facebook designs the application to work. I could very well design an application that lets people store their social security numbers and share that in certain ways. There's no universal law that says an arbitrary indication of relation such as "friend" means that I must have access to your social security number now. Clearly Facebook has not chosen to make that the default and let users easy export emails just by friending. If they did, then yes, I would unfriend people that I don't to give this power to.
Also the UID is the relationship data. You do get that. No need to go out and dump emails which you didn't build. If you do get that info facebook would have to GIVE that to you.
> If you don't want me to have your email address I'm not your friend.
That actually depends on how Facebook designs the application to work. I could very well design an application that lets people store their social security numbers and share that in certain ways. There's no universal law that says an arbitrary indication of relation such as "friend" means that I must have access to your social security number now. Clearly Facebook has not chosen to make that the default and let users easy export emails just by friending. If they did, then yes, I would unfriend people that I don't to give this power to.