nodes and links : secret of social network

A social network is a social structure made of nodes which can be individuals or organizations. The average size is about 120 persons. It is better for individual success to have connections to a variety of networks rather than many connections within a single network
On the internet, social networks exists around msn, blogs or for instance the forums. But also with websites such as “copains d’avant” or others school’s websites where we can find old classmates.
In these communities, an initial set of founders sends out messages inviting members of their own personal networks to join the site. New members repeat the process, growing the total number of members and links in the network
I have different social networks from the schools I went to, and the activities I have done : dance for instance.
Social networks are very important. They are contacts that we will use for anything : a job, a contact abroad, an important adress. The bigger is the network, the more different people we will find in it, and the most interesting it will be for us.
There are some countries, such as japan, where creating a social network is one of the most important things in the life of a person. It depends of the society, but also of the mentalities. In France, the importance of social networks is highlighted mainly in marketing schools such as essec or hec.
The use an the composition of social networks are such important that they are especially studied by a branch of social science.