The International Digital Publishing Forum(IDPF), a global trade and standards organization for the digital publishing industry, has promoted EPUB 3.0 to a final IDPF Recommended Specification for the interchange and delivery format for eBooks and other digital publications.
"EPUB has become the industry standard format for digital publications based on Web Standards that are structured, reliable, device-independent, and accessible," said Bill McCoy, Executive Director, IDPF. "As digital publications evolve from digitized text into enhanced eBooks and new forms of expression, EPUB 3 will dramatically expand the ability of authors and publishers to deliver richer experiences to their readers across disparate devices, in browsers and in apps.
You can learn more about the new format in this article published by O’reilly Media. The article is an easy read and very perceptive even for non-techies. It is a free download from O’Reilly’s website but you must register and check-out as if you were purchasing.