While there has been a lot of buzz about devices like the Kindle or the iPad displacing printed books, savvy publishers have identified techniques for making printed books more interactive. These publishers are combining printed books with quick response (QR) codes. Most of you have probably seen QR codes before, but an image is provided below for those who haven't.

QR codes are two-dimensional codes that enable faster content decoding and contain more information than regular barcodes can. Reading QR codes requires a cell phone with a camera and QR code reading capability, such as Apple's iPhone or a Google Android device.

In a world where mobile phones currently dominate communication technologies, combining printed books with mobile technology makes good business sense. According to data from the CTIA center, 86% of adults in the U.S. currently own a cell phone. What's more, these phones are getting smarter all the time. Of the 265 million mobile phones currently in use in the United States, over 240 million are text-enabled. As of May 2010, there were over 49 million smartphones in use. More than 90% of cell phone owners keep their handsets within arm's reach 24 hours a day, 7 days a week, 365 days of the year. More than 70% of us actually take our cell phones to bed with us and use them as alarm clocks. A study by Unisys revealed that a lost wallet is reported missing in 26 hours. Meanwhile, a lost cell phone is reported missing in 68 minutes.