What is an “online platform”?

The term “online platform” has been used to describe a range of services available on the Internet including marketplaces, search engines, social media, creative content outlets, app stores, communications services, payment systems, services comprising the so-called “collaborative” or “gig” economy, and much more. In this report, an online platform is defined as a digital service that facilitates interactions between two or more distinct but interdependent sets of users (whether firms or individuals) who interact through the service via the Internet. This chapter explains that definition and presents some economic characteristics that are common among online platforms.