The medium is the message

The electric light is pure information. It escapes attention as a communication medium just because it has no 'content.' And McLuhan cites this as an example of how people fail to study media at all.4 For the 'content' of a medium is "like the juicy piece of meat carried by the burglar to distract the watchdog of the mind."5 He sees technological change, specifically new forms of communication, as the prime mover behind history. "The medium is the message."6

Without saying that content plays no role, McLuhan says that by placing all the stress on content and practically none on the medium, we lose all chance of perceiving and influencing the impact of new technologies on mankind, and thus we are always dumbfounded by the revolutionary environmental transformations induced by new media.

McLuhan even goes so far as to say that Adolf Hitler's rise to power had less to do with the actual ideas he articulated than the explosive impact that his radio broadcasts had on German family life in the 1930s.7

4 Understanding Media p. 9
5 Understanding Media p. 18
6 Understanding Media p. 13
7 Understanding Media p. 300