A social network is a social structure composed of persons or organizations connected by one or more types of relationships that share common values and goals.Although the principles of a network is its openness, because it is a social link, the fundamental connection between people is through identity
"The limits of the networks are not limits of separation, but the limits of identity."There is a physical limit but a limit of expectations, trust and loyalty, which is permanently maintained and renegotiated by the communications network. " Principal Social Networks
-Orkut
-Myspace