Books are attention machines. In web metrics, we look at average length of visit per use. I certainly remember when I was running Red Lemonade, I was struggling valiantly to get that up to ten minutes. Other content sites are probably doing the same thing, struggling valiantly for a five-minute average or a thirty-minute average. But look at the book. There isn’t an upper limit on the average time for a book. In a situation where you’re trying to get people’s attention, books are actually incredibly good at maintaining that attention. There’s a certain strand of thinking around publishing which concludes that people’s attention spans are diminishing, and consequently books should follow that diminished attention span by becoming shorter, by adding more things — by adding links, by adding video, by adding audio. That is an enormous mistake, because it is undermining books’ greatest strength, which is their ability to maintain user attention over an extended period of time by requiring the user to use his or her imagination to interpolate the video and audio. To project what those five senses would be experiencing.