Much ink is spilled over the expanding array of video marketplace choices that are competing for the attention of our eyeballs, but much less is usually written about the competition for our ears. As this excellent new Business Week article by Olga Kharif makes clear, competition and innovation in the audio marketplace has never been more vibrant. It's something I've pointed out here before and here's a chart I created for my Media Metrics report to highlight all the new competition for our ears. We've come a long way since the days of my youth, when transistor radios and vinyl records were the extent of audio competition!