people need to stop saying mainstream, for fuck's sake judas priest, iron maiden, slayer, metallica, cannibal corpse, opeth, led zeppelin, pink floyd, etc... etc... are all mainstream
what they are referring to is modern pop music
Yeah, also i think there are levels of Mainstream music or something. Kind of like, Mainstream of overall music (pop music) and mainstream music within Heavy Metal (like Iron Maiden,Judas Priest and etc..)