1 / 30

People prefer e-books when they want fast access and portability, a new study says

An Android-powered e-reader is displayed during a consumer electronics show in Las Vegas, Nevada, in 2010. Slightly more than a fifth of US adults have reported having used an "e-book" during the past year, their ranks swollen by the popularity of Kindles, Nooks, iPads and other gadgets during the year-end holiday gifting season