With the advent of web 2.0, there are now a multitude of sites allowing a group of people or organizations to communicate and maintain social exchanges over the Internet.
Social networks are social media that have become unavoidable and "designate a set of services for developing conversations and social interactions on the internet or in a situation of mobility".
The surfer registered, creates a virtual identity card called most often "profile"; it publishes public or private messages, hypertext links, videos, photos, games ... it has the ability to add "friends", and manage a list of contacts.