KRIS PISTER wants to cover the world with dust. His company, Dust, certainly seems to be shifting the stuff pretty fast. Stacked outside Pister's glass-walled office in the industrial west side of Berkeley, California, are empty cardboard boxes ready to be packed with dust and shipped across the globe. As Pister talks animatedly about his vision, an employee picks one up and Pister whoops with delight: "Ah, great! Another box comes off the stack."

The box is not, of course, going to be filled with any ordinary dust. This is "smart dust", a moniker for tiny, cheap, intelligent wireless sensors that can communicate with each other, form autonomous networks and monitor almost anything: local temperatures, the presence of people, the volume of passing traffic, even the extent of earthquake damage or the health of seabird colonies. You may have heard of it: the technology is already being touted as something ...