This book began with a quiz I got wrong. One of the things I do as the editor of Wired is give speeches about technology trends. Because I started my career in the science world and then learned economics at The Economist, I look for those trends first in hard data. And, fortunately enough, there has never been more data available. The secrets of twenty-first-century economics lie in the servers of the companies that are all around us, from eBay to Wal-Mart. Although it’s not always easy to get the raw numbers, the executives at those companies swim in that data every day and have a great intuitive feel for what’s meaningful and what isn’t. So the trick to trend-spotting is to ask them.

Which is what I was doing in January 2004, in the offices of Robbie Vann-Adibé, the CEO of Ecast, a “digital jukebox” company. Digital jukeboxes are just like regular jukeboxes - a big enclosure with speakers and blinking lights, often found in bars - with the difference that rather than a hundred CDs, they have a broadband connection to the Internet and patrons can choose from thousands of tracks that are downloaded and stored on a local hard drive.