Prezi.com is a web application for making presentations, almost a Powerpoint replacement. It works by zooming in and out, using scale as a hierarchy. It's free for limited use, and costs a subscription for more advanced features. They have been around since April 2009 or 2.5 years.

I don't know exactly which technologies they use, or if any of this is patented. But I think this is a novelty in web user interfaces, similar to the introduction of Google Maps in February 2005.

I think that something similar to Prezi could be used for presenting digitized books, but I'm not sure exactly how. Have you seen any such examples? Please, let me know.

As a first example, I took some scanned book pages and made this little demonstration in Swedish, which you can step through just to get the feeling, http://prezi.com/2iljsxayfrl-/ekbohrn/