I don't like the phrase "sharing economy" because I think that's a misdescription of what's actually happening. There is no sharing, in the sense of concurrent use. What's happening, instead, is that technology is enabling more fine grained transactions in property. If you imagine a set of property rights as a multi-dimensional space, technology lowers the transaction costs involved in splitting up and transacting in sub-spaces of the larger set, and so makes such transactions practical. See: Coase's "The Nature of the Firm."

Sharing is something different. Sharing involves concurrent use of resources mediated by tort-like systems, rather than property-like systems. A real "sharing economy" in cars might be what you end up when cars become self-driving. You won't own a car, but will use whichever car is nearby, and the law will punish various relevant anti-social behaviors instead of violations of property rights.

This distinction is very relevant to things like Uber or AirBnB, because the regulatory challenges there are various issues attached to property rights (e.g. zoning restrictions attached to houses, monopoly privileges attached to taxi medallions).

I agree with Genachowski that state and local governments are a battleground for innovation, but he makes it seem simpler than it is. It's not just a matter of preventing local governments from enacting laws that restrict innovation. It's more basic: renegotiating various privileges that have been negotiated into and priced into property rights. E.g. for better or worse, those who own cab medallions bargained for the monopoly they have, and gave up certain things in the process. Municipalities bargained to create telephone monopolies to serve rural areas instead of building infrastructure themselves. People who bought houses in residential neighborhoods did so pricing in the fact that those neighborhoods would not host hotels. Everyone thought these were reasonable policies at the time. Upsetting those settled expectations in property rights is going to be a very complicated process.

E.g. my personal regulatory interest is in spectrum sharing technology (http://en.wikipedia.org/wiki/Open_spectrum). Technology is getting close to the point where real "sharing" should be possible in radio spectrum. Not just fine-grained subdivision of property rights, but concurrent use mediated by tort-like mechanisms of enforcing "sociable" behavior. I think that technology needs to be rolled out all over the TV bands and the cellular bands. But it's not just a simple matter of flipping a switch. Verizon and AT&T paid billions for their spectrum, under the assumption that there would be nobody else playing in it. You have to kind of see their point of view in opposition to measures to enable sharing on their property. Same for all of the TV companies. They didn't pay for their spectrum, but they made tremendous investments based on certain assumptions, and they've got a right to question changes to those settled expectations.

Incidentally, this is not a new problem. The whole point of property rights is to settle expectations. When the situation changes dramatically, either because of technological or sociological changes, it is a political challenge to accommodate that change without trampling over those settled expectations.