Here is an interesting and enjoyable, though perhaps somewhat broad article about, well, it's a great title - I couldn't describe the article any better. The author is the head of the music theory department, I believe, at Bard College. I'm hoping to develop this, but my off-the-cuff critique is what seems to me the overly general way in which popular music is treated. For example, the icons of pop music through the generations are identified, off-the-cuff, as Bob Dylan to someone else to someone else to Kanye West. While perhaps (and perhaps not) there is a parity in terms of sales and celebrity between Dylan and Kanye (even that seems doubtful considering what a huge - huge - celebrity Dylan was), I'd make a tentative argument that there's a qualitative difference, artistically between Dylan and Kanye. Not to knock Kanye, and I admit to not having heard what is supposed to be his opus, My Beautiful Dark Twisted Fantasy, but the first guess I'd hazard would be that Bob Dylan's artistic chops (when it comes to songwriting alone!) make an equivalence between him and Kanye questionable.
Finally, Pop music just seems too big to be categorized as it is here. For example, in terms of sales and media attention the three-to-four-minute single might be the dominant form, but since the article is also about artistic and cultural influence, there are many, many pieces of music which I'd consider Pop (though I could be wrong), such as Can, incidentally sampled at one point by Kanye, who don't limit themselves in that manner. Pop just seems to big - there's all sorts of experimental rock, electronic musics (house, techno, IDM, whatever), even jazz, if we are going to throw it in there.