As many as 25,000 fans show up for Miku Hatsune's concerts. But their idol isn't a person -- she's the 3D hologram of a Manga character. Miku Hatsune will be 16 forever. Dressed in an armless school uniform with a short mini-skirt, she sings pop songs in her high voice. It's generated by Japanese musical synthesizer application "Vocaloid 2", which allows users to play songs with her voice. Now more than 100-thousand fan-produced compositions are circulating on the Internet. This makes Miku Hatsune a truly "user generated" pop star.