Those of us who enjoy looking out of airplane windows received a special gift last year with the debut of Google Earth, a virtual globe that can be manipulated with a mouse. The globe itself is composed of satellite photography that has been taken in the past three years, and the data are updated piecemeal every couple of months. Using Google Earth is similar to driving a satellite. With a few keystrokes, you can zip from Paris to New York to Tokyo. Where the photographic data are particularly rich, you can zoom in and see the shadow cast by a woman walking down the street. You can also simply fly around. At first, this is all very interesting, but I suspect that most people locate their house, check out the Grand Canyon, then leave Google Earth to clutter up their hard drives. For the chosen few whom Google Earth calls out to, however, it's powerfully addictive—sort of like freebasing your sixth-grade Earth science class.