Economic power in the Internet has been traditionally unregulated, due to the fact that the digital markets has been created very recently. However, we are now facing the consolidation of few global online platforms who tend to become dominant on specific markets. They are not only technological operators, they are rather market intermediaries that intercept an important share of the added value that flows between producers and consumers, creating monopolistic or oligopolistic double-sided markets. This situation is attracting increasing attention of competition enforcement authorities as well as regulators, consumers, and privacy watchdogs in the world. The EU is now in the process to pass ad hoc pro-competitive legislation for online platforms, while similar proposals are debated in US, Latin America, and Asia. Is the time for ex-post competition rules definitively over for the Internet, and should we instead rely on ex ante regulation, as it was done in the 90’ for telecoms?