[Text available only in English] There are many networks that make up the contemporary world: biological, neural, electrical, railways, television, mathematical, data transmission... But the Net par excellence today is the Internet. And if you say network, everyone will add social and virtual communities will immediately come to mind. But they existed long before Facebook, Twitter and friends: a social network is infact a group of people connected by several bonds, ranging from friendship to casual acquaintances, from family ties to job relationships, to contact (sporadic or on a regular basis) with “friends” or “followers” on the Internet.
How many...