linked in the above piece is a great rant/article about the limits of interfaces: http://worrydream.com/ABriefRantOnTheFutureOfInteractionDesign/responses.html

"It won't be long before almost every one of our daily activities is mediated by a "computer" of some sort. If these computers are not part of the physical environment, if they bypass the body, then we've just created a future where people can and will spend their lives completely immobile. Why do you want this future? Why would this be a good thing?"