Social networking is the practice of expanding the number of one's business and/or social contacts by making connections through individuals.
While social networking has gone on almost as long as societies themselves have existed, the unparalleled potential of the Web to facilitate such connections is only now being fully recognized and exploited, through Web-based groups established for that purpose.
Based on the six degrees of separation concept (the idea that any two people on the planet could make contact through a chain of no more than five intermediaries), social networking establishes interconnected online communities (sometimes known as social graphs) that help people make contacts that would be good for them to know, but that they would be unlikely to have met otherwise.
Depending on the social media platform, members may be able to contact any other member. In other cases, members can contact anyone they have a connection to, and subsequently anyone that contact has a connection to, and so on. Some services require members to have a preexisting connection to contact other members.