Mr. Keen argues that the democratized Web’s penchant for mash-ups, remixes and cut-and-paste jobs threaten not just copyright laws but also the very ideas of authorship and intellectual property. He observes that as advertising dollars migrate from newspapers, magazines and television news to the Web, organizations with the expertise and resources to finance investigative and foreign reporting face more and more business challenges. And he suggests that as CD sales fall (in the face of digital piracy and single-song downloads) and the music business becomes increasingly embattled, new artists will discover that Internet fame does not translate into the sort of sales or worldwide recognition enjoyed by earlier generations of musicians.