Hatsune Miku
Since the success of her Vocaloid 2 package led to an expansion of marketing possibilities, most of the mass marketing has come after her initial release as a response to her popularity and has been on going since 2008. Even with the addition of other Character Vocals, Miku's name continues to be used as the primary source of marketing for Crypton Future Media, to the point where most products for their Vocaloid related products will usually only feature Hatsune Miku's name. In March 2012, the Nomura Research Institute estimated that the sales of all Hatsune Miku brand goods added up into the region of since her release in 2007. Her name is easily the most recognizable of all Vocaloids.
Megurine Luka
Megurine Luka was originally designed to be the first Vocaloid of the "Character Vocal Series" that Crypton Future Media would release and was going to be called "Hatsune Miku", designed to be capable of singing both English and Japanese vocals. However, the concept was put on hold and the name was used for another character, making Luka the 3rd vocal of the "Character Vocal Series" to be released instead.