jbcohen, please add a little more to your URL referral so we know more about the subject. Thanks for the reference though.
What I found most interesting was:
"While e-book reading is markedly growing, printed books still dominate the world of book readers. In a December 2011 survey, 72% of American adults said they had read a printed book and 11% listened to an audiobook in the previous year, compared with the 17% of adults who had read an e-book."
I didn't know that many people listened to audio books. More than 1/2 as many as read an eBook.