A social network is a virtual community very useful in social sciences in order to study relationships between individuals, groups and organizations.This community works as a place where people can meet, talk and compare with others. The nature of social networks varies from one site to another and also there are so many reasons why people choose the same one. We can definitely admit that with the advent of the Internet the society has changed. Everything can now be looked at from a different point of view.  In a computer mediated communication context, social pairs exchange different kinds of information, including sending a data file or a computer program as well as providing emotional support or arranging a meeting. With the rise of electronic commerce, information exchanged may also correspond to exchanges of money, goods or services in the "real" world.