As I stepped on the bathroom scale, my life flashed before my eyes. I looked into the mirror and saw a graph, magically overlaid on my reflection. The red line plotting my weight over the last year looked like the Dow Jones average, with little bumps during the Thanksgiving and Christmas eatathons. It was a sobering image.

That system, called NetWeight, is the invention of MIT Media Lab researcher Brad Geilfuss. With it, Brad argued a fundamental thesis: the way to revolutionize medical practice is by connecting our bodies more directly to the medical system. Since most of us are a captive audience for a few minutes a day in the bathroom, he started there. The scale was a networked sensor. The mirror gave you an "inner view": it contained a Silicon Graphics computer and a video projector that overlaid live graphics on your reflection. The weight graph could appear on your beer belly.

Before you run screaming from the littlest room in your house with visions of Big Brother watching your every excretion, let's think this through.

The problem of staying in touch with our health goes far beyond just monitoring flab. For example: there isn't a person on the planet who has seen a simple, cogent picture that traces the health of his or her heart over the last few years. This can have grave consequences.