The document discusses key concepts from chapter 2 of "A Critical Introduction to Media and Communication Theory" including: 1. Media can be viewed as institutions, organizations, products, or technologies. 2. Harold Innis' ideas of time bias and space bias which influence how media distribute information over time and space. 3. Marshall McLuhan's concepts of "the medium is the message" and how different media act as "extensions of man" and influence society in different ways. 4. McLuhan's distinction between "hot" and "cool" media and how they require different levels of engagement and participation.