This question pops up a lot. "Rock & Roll" is a generic term for popular non MOR music of the 60's and early 70's and covers a wide range of genres, generally following the format of "Rock & Roll" radio stations of the time. It didn't really begin to break apart into sub-genres until the introduction of the Progressive Rock format in the late 60's and has shattered into little bits and pieces with format nitches for every taste. The list below shows all the formats that are measured for raitings by Arbitron:

http://media.about.com/gi/o.htm?zi=1...me/formats.htm


Remember, early pop radio used to play many styles of music butted up against each other. Look at the variety of stuff on the Keener-13 charts back in the day. It was all pretty much considered "Rock and Roll", from Pet Clark to Blue Cheer, but the term may actually be out of date by now, what with the fracturing of both radio formats and styles. Most people who listen to radio now a days don't seem to want variety, they want Hot AC, or AOR or AAA, or New AC or Urban or a hundred other "styles", and are devoted to their individual taste to the near exclusion of other styles of music.

[[phew.)