Apple's purchase of PrimeSense last week had all the tech industries howling. The Israel-based company's motion tracking technology had largely informed early versions of Kinect, Microsoft's motion-tracking and voice command interface for the Xbox 360 gaming console. Was Apple planning to use PrimeSense's expertise in motion tracking to propel its gadgets into a new era of universal motion tracking capability? Maybe not, says former Washington Post tech journalist Jessica Lessin. It's all about PrimeSense's other, lesser-known, claim to fame: 3D indoor mapping.