This demographics of cool is a devolution away from segmentation of smart cross-cultural or multicultural marketing strategy. As a society, the western cultures are more and more melted culturally, and the meaningful identity is changing according to the situation you are at the moment. The categories are not relevant anymore and the identity is evermore complex.
Still, the demographics of cool is more than just trying to define a new meaning for demographics. Steve Stoute is arguing that out of hip-hop, a new culture has emerged, one "shared mental complexion" that no demographics can capture. Age, race and income don't matter. Only the mind-set matters. 34-old Indian bluecollar worker, 16-year old high school kid from the UK and 45-year old whitecollar from Japan worker are all the same demographics. In the modern world, urban has nothing to with place or race and everything to with attitude.

These consumers, choose what becomes cool and, more crucially, decide when something isn't cool anymore. Remember the champage Cristal's fall from grace, just because Jay-Z said so? When the importance is the psychologic, the demographic data and quantitative research become meaningless. Because when you define a market by how people in it think, not by who's in it, the definition process is far mor complex and expensive.
Just think of the Apple iPod's now-iconic silhouetted hipsters sporting white earbuds, striking poses. You can't tell if those silhouettes are 18 or 34 years old, rich or poor, black, white or asian, from Helsinki or from Tokyo. All you know for sure is that they're cool!