Three years ago, Zenith Media's Tom Goodwin noted: "Uber, the world's largest taxi company, owns no vehicles. Facebook, the world's most popular media owner, creates no content. Alibaba, the most valuable retailer, has no inventory. And Airbnb, the world's largest accommodation provider, owns no real estate. Something interesting is happening."
Mr Goodwin observed that "these companies are indescribably thin layers that sit on top of vast supply systems (where the costs are) and interface with a huge number of people (where the money is)". He concluded that "the interface is where the profit is" and "trust is the most important asset".