Internet economics, digital economics As an introduction to a series of contributions about Internet economics, the present paper has three goals. We firstly recall several basic facts and principles characterizing the morphology of the Internet, its operating system, its regulation procedures, as well as its rapid success which today makes it the "net of nets" as well as a universal platform for information exchanges and commercial transactions. Then we show how the economics of the "Internet system", by creating original types of relationship and coordination between economic and social agents, acts as a catalyst generating mutations in market structures and hierarchical settings, thus synthesizing, as in a laboratory, the scheme of an e...