 This concept of two-sided markets has been mainly theorised by the French economists Jean Tirole and Jean-Charles Rochet.Two-sided networks can be found in many industries, sharing the space with traditional product and service offerings.Example markets include credit cards (composed of cardholders and merchants); health maintenance organizations (patients and doctors); operating systems (end-users and developers); yellow pages (advertisers and consumers); video-game consoles (gamers and game developers); recruitment sites (job seekers and recruiters); search engines (advertisers and users); and communication networks, such as the Internet.