PDF is meant to be a digital equivalent to paper, thus it does not scale well to different screen sizes. An objective of PDF is for a document to look the exact same no matter where you open it.
ePub text and images can be reflowed to fit a smaller/larger screen, it is not proprietary, file sizes are smaller, and is overall an ideal format for ebooks.
That's interesting, but I'd expect their website to actually use their own product appropriately when viewing from my mobile devices. The "examples" page works, but isn't really in a well designed format - font headings are too large, text is pushed all the way to the far left without a single pixel margin causing it to look like the page should scroll horizontally, etc...
I like the concept of what they're doing, but if their site is using it, then I'm not interested.
