Firms like Google, Facebook and Amazon–and new ‘sharing-economy’ firms like Airbnb and Uber–like to define themselves as ‘platforms’. They don’t face a traditional market, in which the firm produces a good or service and sells it to a population of potential consumers. They operate, instead, in what economists call two-sided markets, developing the supply and demand sides of the market as the lynchpin, connector or gatekeeper between them.
