It’s important to understand the distinction between apps and eBooks, as it's something that often confuses both publishers and consumers. It basically comes down to formats; apps are mostly native iOS or Android software, whereas eBooks are documents of a particular format, such as the open standards EPUB and Mobipocket (.mobi).
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And eBooks can be further distinguished from “enhanced eBooks,” which use formats such as ePUB3 for iBooks (Apple) and Kindle Format 8 (KF8) for Kindle Fire (Amazon).
eBooks were the first to appear on devices such as the Kindle, and have very limited interactivity. You are mainly able to flip the pages, search for content, or highlight words to see a dictionary definition. These devices also allowed font size to be increased to enable visually impaired readers enjoy books more easily. This gave publishers the unforeseen benefit of regaining a large population of users who couldn’t read printed books.
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Enhanced eBooks (ePUB3) are a new digital publication standard that allows easy integration of video, audio, and interactivity. I expect this format to advance the future of textbooks and other educational material. Future textbooks might be able to "read themselves" with audio narration, perhaps preventing students from actually reading. But the benefits outweigh the downsides; for example, the new text books might also offer the ability to make and share annotations without destroying the book, interactive self-tests throughout the chapters, and generally a much more enjoyable learning experience.
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There are a few exceptions where this type of interactivity is actually a success. For example. one of the first books published as an interactive app for the iPad was Alice in Wonderland.
http://itunes.apple.com/us/app/alice-for-the-ipad/id354537426?mt=8
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This book was a phenomenal success though offered nothing but eye-candy interactivity. When the app was first published, the reviews called it "a reinvention of reading” that made clever use of the accelerometer to make Alice grow as big as a house or to throw tarts at the Queen of Hearts and watch them bounce.
http://www.huffingtonpost.com/2010/04/14/alice-in-wonderland-ipad_n_537122.html
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Although these activities through the 52 pages of the book are fun, I think they distract from the actual story. The reason this book was such a success is due its having been published when the iPad was fairly new, and touch interactivity was still an exciting experience.
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Cozmo's Day Off is an interactive eBook that was on the top-seller list for many months, and is packed with interactive elements that made it a great success ..
http://itunes.apple.com/us/app/cozmos-day-off-childrens-interactive/id409177911?mt=8
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Heiko Idensen