What is Rock music?

[asuna]

to me true rock is played by a band, not some singer singing solo to a rock tune playing in the background (sadly that includes ayu ><)

and it has to have guitar riffs!

jrock bands, american bands (oasis and U2 ^^), even the beatles, are my rock

[simonlau]

Wiki says

Rock music
Stylistic origins: Rock and roll, ultimately blues (mostly jump blues and Chicago blues), country music and R&B
Cultural origins: Late 1940s United States
Typical instruments: Guitar - Bass - Drums-
occasionally Keyboards
Mainstream popularity: Much, constant and worldwide since the 1950s
Derivative forms: Alternative rock - Heavy metal - Punk rock
Subgenres
Art rock - British rock - Christian rock - Desert rock - Detroit rock - Experimental rock - Garage rock - Girl group - Glam rock - Glitter rock - Group Sounds - Hard rock - Heartland rock - Instrumental rock - Jam band - Jangle pop - Krautrock - Post-rock - Power pop - Protopunk - Psychedelia - Pub rock (Aussie) - Pub rock (UK) - Rock en espanol - Soft rock - Southern rock - Surf

well, i think most of us consider pop-rock as rock.
Ayu did good pop-rock but that's not ROCK.