In my opinion, assigning a value of even $28b to an app that could be duplicated by a single developer in under a week is probably a bad idea. Let's remember that most of the money they've blown has not gone into capital expenditures - there isn't a giant fleet of cars they own that could be sold if they fail, for example. They've spent almost all of the money subsidizing rides to win customers and drivers - both of which could leave the platform for the next great app in a heartbeat. They have not gained any assets as a result of their massive expenditures.

My personal opinion is that anyone investing in this company at any 10 figure valuation - much less 11 figures - is probably poised to lose most of their investment. We've seen through companies like Theranos how billions in perceived value can vanish overnight when business realities and investor expectations are mismatched. While these two companies appear to have reached high valuations through different means - Theranos through fraud and Uber through unprecedented hype - they may ultimately wind up in similar situations.