Japanese pop star Hatsune Miku is a 16-year-old singer... a stylish, blue-haired pop princess who's topped the charts there, sold out stadium concerts, and garnered tens of thousands of Facebook fans. Hatsune is also a 3D hologram: a singing virtual avatar created by a Japanese technology firm, using Yamaha's Vocaloid voice synthesizer. Unlike the Britneys and Gagas of the world, she can perform simultaneous concerts, meet all her fans' demands, and never needs to go to rehab.