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.
On the Web today, social sites such as Facebook and Twitter have expanded the concept of size by orders of magnitude. They allow families, friends, colleagues, celebrities and politicians to communicate with each other and the world. See social networking
and social networking site