Hatsune Miku, the character, is a 16 year old girl with long, turquoise twintails and a modified school uniform. Her design was created and illustrated by KEI. She comes from a "distant future where songs are lost". Initially marketed to professional musicians like other vocalists before her, her character was the catalyst for the VOCALOID boom online in the late 2000s by otaku fandom on niconico and forum boards like 2chan. Because she has little canon besides her character information and can be portrayed in many different ways as a result, her character is ripe for fan creation and modification, having hundreds of thousands of unofficial fan portrayals and derivatives, even by Crypton Future Media themselves. Miku has since become a mascot for the internet itself and the expression of individuality and artistic merit in a new, digital landscape. She's now known as one of the biggest "virtual popstars" in the world, having a multitude of live concerts, games, figures, merch tie-ins, official collaborations, and much, much more.
Since 2011, she's been heavily involved with the snow festivals in Sapporo, her hometown. Her campaign, entitled "Snow Miku", allows fans to make their own designs for the occasion and overall promote Hokkaido. A spring version, entitled "Sakura Miku", is made for advertisement in the cherry blossom season. She's also part of a campaign for GOODSMILE RACING, a subsidiary racing team of figure company GOODSMILE that often releases Miku figures, entitled "Racing Miku". A new design for the team has been released every year since 2008.