As another followup, how does the valuation compare to a company like mytaxi.com? App and service seem functionally equivalent, except that pricing is done by in-taxi meter. Lots of Berlin cabs run both MyTaxi and UberTaxi.

Another point of comparison is Juno in Manhattan which took a smaller cut from drivers in order to poach the best ones from Uber and Lyft. I've always felt that competition for drivers will drive the profit margin down to what's needed to support a small team of developers pretty quickly.

The trouble with this, and several other recent companies, isn't whether there's a business there. Cab via app? Way better. I love it.

It's still an open question whether there's a 100 Billion Dollar Business. That's what they sold to investors, and since they cashed the check, that's what they must deliver.

Or some hedge fund will buy the pieces for pennies on the dollar and sell them for scrap.