An information society is a society in which most of the people produce and consume information. In such society, services are the most "popular" field where people work, and information technology plays very important role.
This is one of the society trends of the 2000s. The information industry in form of TV, newspapers and such were already there, and the 1990s brought the computers and Internet as the everyday things people use to get information.
No, I'm not a sociologist. It's just that this term comes up way too often when talking about relationship between technology and society. /msg if I'm completely wrong.