(1) Internet definition: An online service for publishing/posting comments and opinions as well as re-posting information from other users. The terms "social network" and "social media" are synonymous. See
social networking service and
social network rankings.
(2) Non-Internet definition: An association of people drawn together by family, work or hobby. The term was first coined by professor J. A. Barnes in the 1950s, who defined the size of a social network as a group of 100 to 150 people.