I was back on John Walter's blog looking for the Nick Carr link, and in the process noticed a link to Lance Strate's blog and an essay Strate published in McLuhan Studies Issue 3, "Media Transcendence." A few paragraphs jumped out at me:
"McLuhan's media ecology approach is in part a form of materialism, based on analysis of the human body and its extensions. In contrast to Marx's dialectical materialism, however, McLuhan gives us a rhetorical and grammatical materialism. But McLuhan's perspective is also grounded in the North American tradition of pragmatism. By medium, McLuhan refers not only to the material, but also to the means, modes, and methods by which we operate on the material world."
"'The medium is the message' expresses with perfect economy the idea that how we do something has much to do with the results we obtain, no matter what our original intent may be. This idea is present in Henry David Thoreau's observation that "we do not ride on the railroad, it rides upon us." It is there in Mark Twain's wonderful quip, that when you have a hammer in your hand, everything looks like a nail. It is entirely absent, however, from the slogan of the National Rifle Association, that "guns don't kill people, people do." If you believe that guns themselves have increased the potential for violence, then you are with McLuhan."
I'm going to have to let those paragraphs speak for themselves--I'm blogged out.