I think it will have to be negotiated as we go.

I think this is correct, especially if we think ten + years out.

Employees will register with what they use and into an organization's system, and some sort of tagging or watermarking & bookmarking will divvy up what goes were.

An early signal was the Forrester policy undertaking re: employee blogs earlier this year. I'm not aware of how things have gone since they implemented the new policy.

But the issue won't go away .. it will only grow.