Are blackness and whiteness useful concepts in the study of popular music?

It is difficult to define what makes black music 'black', and what makes white music 'white'. Both have their stereotypes, however there have been artists which break the racial mould, like Eminem, a very successful white rapper.

According to Hatch & Milward, "pop music has always depended upon the interaction between white and black traditions". This can be seen to be true, as much of popular music can be traced back to having black origins. Arguably the greatest performer of all time, Elvis Presley, was influence by gospel music, which undoubtedly shaped him into the "white man who had the Negro sound and the Negro feel".

Blackness and whiteness may have had more of an effect as a concept in the study of popular music decades ago when race may have created a problem in music consumption. However this could also be disproved when looking at Marnie Smith's 'Crazy Blues', which was promoted openly as being by a black artist in 1920 and exceeded all expectation by becoming the first million selling single.