Group

According to Rainie and Wellman (2012), groups tend to have precise boundaries for inclusion and exclusion. They are internally organized and hierarchically structured and "governed by a culture of generalized exchange."They are also stereotypes for relationships."Groupiness" may be used to "bolster their power and compliance to group norms in what sociologist Emile Durkheim called "mechanical solidarity"" (p. 35). They also offer stability which people crave, and being a member of a group can be easier than "maneuvering through murky, shifting sets of relationships at home, work, and in the community" (p. 35).

Groups are different than networks.

References:

Rainie, H. & Wellman, B. (2012). Networked: The New Social Operating System. Cambridge: MIT.