Turns out the theories about this have changed over time. This fascinating article reminds me of the great Simon Frith essay, "Why Do Songs Have Words?" Frith posited that pop song lyrics teach the young men of our decidedly unpoetic era the language of courtship.
A Nielsen/Netratings survey suggests they might. Favorite alcoholic beveridge? Hard cider. Favorite car? VW. Favorite TV network? Cartoon Network, followed by BBC America and HBO.
One of my favorites was left out. From Anthony Burgess' Earthly Powers: "It was the afternoon of my eighty-first birthday, and I was in bed with my catamite when Ali announced that the archbishop had come to see me."