From Devin Coldewey – Amazon Throws A Minor Curveball With HTML5-Powered Kindle Format 8:
Amazon has announced an update to the Kindle file format integrating many HTML5 tags and CSS attributes. Many expected a concession by Amazon in the form of an EPUB-compatible upgrade, and this comes as a slight surprise — but it’s a natural evolution of the format, really, and of course everyone is already familiar with the toolset.
In a way this makes Kindle formatted books nothing more than extremely long webpages, but that’s really a matter of perspective. Flexible layouts and well-known rules for handling text, fonts, images, and so on mean that the file format is adaptable to many devices, zoom levels, resolutions, and so on.
The full list of new tags and such can be found here; there’s no video or audio tag, tellingly, but apart from that it seems a fairly normal collection of HTML elements and CSS stuff.