Sharing economy firms, based on online platforms, have become strong competitors of traditional firmsin many services sector, including the taxi industry. The aim of this article is to provide an economicframework for the analysis of this rivalry. Besides the literature on sharing economy, the characteristicsof online platforms are summarised, which explain the quick expanse of successful sharing economyventures. Based on the theoretical literature it is shown that for service providers, the choice betweensharing economy platforms and traditional firms resembles the ”standard wars”, the competition betweentechnological standards. A coordination game is presented to analyse the competition between taxicompanies and Uber. The model not only reveals the different equilibria and the possible strategies ofthe players, but also shows the importance for adequate regulatory policy.