Marshall McLewan referred to television and film as "cold media," as opposed to the hot media of books and papers. A hot medium makes a person think, and lets their brain fill in the visual and auditory blanks that result from interpreting something you read. A cold medium spells everything out for you and leaves nothing to be discovered by the mind.

Essential Essay: What is the Meaning of The Medium is the Message? by Mark Federman, Chief Strategist, McLuhan Program in Culture and Technology

"In a culture like ours, long accustomed to splitting and dividing all things as a means of control, it is sometimes a bit of a shock to be reminded that, in operational and practical fact, the medium is the message. This is merely to say that the personal and social consequences of any medium - that is, of any extension of ourselves - result from the new scale that is introduced into our affairs by each extension of ourselves, or by any new technology." (McLuhan 7) Thus begins the classic work of Marshall McLuhan, Understanding Media, in which he introduced the world to his enigmatic paradox, "The medium is the message." But what does it mean? How can the medium be its own message?http://www.mcluhan.utoronto.ca/article_mediumisthemessage.htm