Hatsune Miku
Hatsune Miku was the first Vocaloid developed by Crypton Future Media after they handled the release of the Yamaha vocal Meiko and Kaito. The name of "Hatsune Miku" was conceived soon after the Vocaloid 2 announcements, when an English and Japanese vocal were developed for the character. The intended design was delayed and later used for Megurine Luka instead. Miku was intended to be the first of a series of Vocaloids called the ""Character Vocal Series"", which included Kagamine Rin/Len and Megurine Luka. Each had a particular concept and vocal direction.
Supercell (band)
Ryo chose to distribute his music on Nico Nico Douga because he liked the website along with its response system, which enables user's comments to appear overlaid on the video screen. Ryo did not originally intend to use Hatsune Miku as the vocalist for his songs, and most members of Supercell did not even know of Miku until after "Melt" gained popularity. Since Ryo did not know any singers, he was recommended by his friends to use Miku, which he thought was a good idea since videos using Miku were already widely being distributed on Nico Nico Douga at the time.