"It's in the Internet, we saw it. But we went to the real office and it's not there!"
My cleaning lady complained about her husband's pension fund. What impressed me was that she gave more importance to a information that it is the Internet than some "oficial" government paper.
Maybe it's a naive idea and I'm not looking deep enough in the private property's issue, but I imagine a system of land registry initially walking side by side with the oficial registry, until people gain confidence and see coherence in the decentralized information.
The protocol divide the earth's lands in pieces (XY Coordinates, like pixels) and that can be made more divisible if needed.
Communities and buildings can use Multi-Sig functions.
I'm not seeing yet a solution for rewards/incentive in running such network other than have accurate information about who owns the land.
Another drawback is that you'll have to attach a real name (Decentralized Naming?/Pseudonym/Public Key?) to a piece of the land.
The objective is just to point who owns what, not to enforce some action to resolve disputes.
I don't even imagine the nightmare that is getting your land hacked!
Yet my thought is: Decentralize All the Things!!!