The climate of eBooks is changing (honestly when hasn’t it). With the release of EPUB3 we developers have access to a higher level of interactivity for readers. With the capabilities of CSS3 and HTML5 tied into EPUB developers are all carefully testing the waters of what they can make available to consumers through ebook readers.
Now you may be asking, Why am I not seeing this in ebooks now? Well chances are that publishers are testing to see which devices will actually be able to read EPUB3 documents. I’m sure I’ve said it before (and undoubtedly will say it again), older readers oftentimes don’t have the capacity to handle new code. Think about it, the original Kindle came out almost a decade before EPUB3 even existed. They simply couldn’t have planned for that. Those of you with tablets are in luck. Tablets, since they are essentially mini-computers are subject to regular software updates and should soon have close to full EPUB3 capabilities.