SHE has long, straight, turquoise-coloured hair, extending nearly to her ankles, and dresses in a futuristic-looking mini-skirt uniform.

Unlike other Japanese songand- dance idols, she has overly large green eyes and the figures "01" visibly tattooed in red on her left arm. Her official site states her age as 16, height 158cm, and weight 42kg. She's not quite tall, but decidedly cute.

But the scenario where adoring fans rush up for autographs may still be far off - not for the lack of popularity, but because Hatsune Miku is not quite human.

She's virtual.

Hatsune translates to "first voice", and Miku to "future". She made her debut in a box, Aug 31 last year, as a music creation software that allows users to use synthesised vocal samples to create songs, simply by inputting lyrics and melodies.

Hatsune's voice is based on audio samples of 24-year-old voice actress Saki Fujita, who has done roles for TV animation shows such as Happy Seven and Bleach.

Final singing results range from quite human-realistic to cartoonish, depending on how much tweaking the user does to additional audio parameters like dynamics and vibrato.

This technology isn't entirely new. Vocaloid, developed by Yamaha, internationally- renowned for music instruments, has been available since 2004.

The second-generation engine was released in 2007, making usability and synthesis quality improvements.

What's ground-breaking about Hatsune isn't quite about the synthesis technology, but how it has turned into Japan's latest user-generated content craze.

Anybody can easily blog, share photos and videos. But not everybody looks, sings and dances like an idol. Hatsune has, in effect, become the virtual stage-persona for even the most karaoke- aversed.

While the first-generation Vocaloid products sold 3,500 copies in total, Hatsune sold 30,000 copies in six months - a feat in the "virtual musical instruments" software category where yearly sales of 1,000 copies is considered a hit. Hatsune has been marketed as an animation- styled idol character with matching voice characteristics to attract a larger audience including users who have never thought about making music.

Other than licensing terms binding the user not to synthesise derogatory or disturbing lyrics, Hatsune users are free to create almost any music, be it for commercial or non-commercial use, and retain any rights and obligations arising.

You can find Hatsune singing many songs. On Nico Nico Video (nicovideo. jp, user-registration required), the Japanese-equivalent of YouTube, over 23,000 search results are returned.

Hatsune had mostly appeared in 2D graphics in videos, until a fan going by  the handle name of Higuchi Yuu programmed a free 3D-animation tool.

With MikuMikuDance, users can make Hatsune do things like swing her arms and perform dance footwork a la Para Para Paradise.

Accompanying video tutorials demonstrate how easily one can just mouse-click on Hatsune's body parts and joints and create movements without coding up a sweat.

In just over two weeks more than 110,000 downloads were made. 3D-animated videos of Hatsune soon surfaced, further propelling the wave of user-generated Hatsune content.

She has been appearing in user-created video mash-ups, flash games, icon collections, and more.

She will also appear in an upcoming Nintendo DS Lite game, playing the role of a music instructor. One can even sing some of her hits in karaoke chain-parlours.

Now the virtual star's appeal is extending beyond Japan.

English-language based fan-sites such as mikumiku.info and mikufan. com provide links to the latest clips and songs.

Users have also found ways to enable the English-interface in the Hatsune Miku software and written Mandarin and Spanish interfaces.

Cosplay fans are paying homage by dressing up in her signature virtual idol garb.