Modern Rock is music with a progressive beat, typically consisting of guitar, drumset (and other percussion instruments), vocalizations. It is typically favored by those in the 16 to early 40s age group and particularly by Collegiate musical observors."
Evanescence, Three Days Grace, Dido, Within Temptation, Breaking Benjamin, OURS, AFI.
Modern Rock is a style of music.
Modern rock is a radio format often wrongly used interchangeably with Alternative Rock or other genres. The simple fact of the matter is that since "Modern Rock" just refers to recent bands and actually doesn't actually follow any specific style, it is not a genre at all.
Person A: i luv modern rock, lolz
Person B: That makes no sense.