The page is in Japanese so here's a rough (automated) translation (EDIT: English info here, thanks baggagelizard!):
"By clear and natural English pronunciation, and strong articulation and smooth vocal music of all genres do sing honestly. It is a library can use all new features of the VOCALOID4, especially with the excellent compatibility with the 'as'. Rock, soul and blues magazines, artistic voice graininess, to appear a bit Rough (rough), voices and intensely Harsh ear-piercing (Hirsch), voice, can pursue various vocal expression."
Vocaloid4 Editor (sold separately) or "Vocaloid4 Editor for Cubase" is required to use the Cyber Diva.