Interesting article from the Wall Street Journal:
As a result, some of the biggest sellers of the year -- from Disney's "High School Musical" and "Cheetah Girls" soundtracks to the "Kidz Bop" series -- are those aimed at the grade-school set.
By contrast, longstanding industry staples like rock and even hip-hop have far less commercial potential. "When we sell 150,000 albums from a new rock group, we think we've set them up pretty well," says Bob Cavallo, chairman of Walt Disney Co.'s Buena Vista Music Group. The "Hannah" soundtrack, meanwhile, sold nearly 274,000 copies last week alone.