The organizations responsible for publishing EPUB and HTML as standards are working together on ways to make a mini-Web site that you can browse offline, on making an e-book be part of the Web, all using open standards and part of the Open Web Platform.
For the Libre world this means Web browsers and ebook readers move towards each other, so that the skills and tools you need become more closely aligned. It means documentation, tutorials, guides can be both on the Web and on a tablet or other reader.
But in the longer term it means another nail in the coffin of propritary hardware, proprietary apps, proprietary readers, because the ubiquity of the Web commoditizes everything.
It also means asking why there is a difference between an application and a document at all and what that question means for the Libre Graphics ecosystem.
XML Activity Lead, World Wide Web Consortium, Canada