It's a strange twist on the eBook story, but several recent surveys have suggested that readers who enjoy books on devices like the Kindle are often buying more physical books. John C Davorak, host of the video podcast Cranky Geeks, who seems to be the eBook man for PC Magazine wrote in a recent article -
"I'm reminded of my son's reaction to the Kindle. He got a Kindle because he thought it would be a nice way to make the library of reading more practical and compact. The more books he read on the Kindle, the more books he decided he had to buy in hardcover or paperback edition"
At a time when the widespread opinion is that eBooks will kill traditional books, it would be perverse if the new technology actually increased physical book sales.