I just recently read a short article about a new form of digital pub called a "vook" - a combination of video and book. The article 
highlighted a couple of fiction novels that had tossed in video clips throughout the pages. The upside? These digital pubs were iPhone ready, something still being figured out by many of the publication formats out presently. The downside? Well, it seemed that the videos were somewhat of a disruption when reading the vook.
Thinking about my own experience with reading fiction - and I do love a good absorbing story as part of my reading most days - it feels to me that this particular instance of digital publishing is really not the best use of technology. I've been considering whether or not I feel this way due to it's being fictional text or just the disruptive nature of media in general. I've decided it's because it's fiction. I also adore good movies. Sometimes not even good movies, but just really entertaining ones. I'm a sucker for eye candy - I tell myself it's because I'm a designer and not some baser titillation. But when I'm absorbed in a good fiction book, my imagination is really playing the show in the background. I'm even careful about when I watch a movie or show based upon a novel I enjoyed - I really don't want my own imaginative process to become dictated by someone else's. Given this, I imagine I would really NOT enjoy video clips popping up while I was reading. MAYBE beautiful animations. And preferably, dancing around the edges of the page, waving at me discreetly from the sidelines. THAT could be fun... (note to self...)
But I don't believe that as a whole the mixing of media and text is doomed to failure at all. I have frequently seen how having movement or audio greet you on a page can be pleasant and effective, especially with clear tools for control (play, stop, what have you) given to the reader. I've also seen it overdone, probably indulged in it myself. It's hard not to become overly enthusiastic once you can start creating magical Harry Potter newspapers. I love it. I also think it's going to transform textbooks, newspapers, magazines and maybe even narrative fiction in the hands of tasteful designers. Including interactivity with websites, educational video, audio instruction - I would hands down love to be saving paper and having my sons using textbooks like these (plus - they wouldn't keep LOSING them.) I can see a subscription to National Geographic or other informative magazines being a monthly launch into whole new experiences. Yes, I can create the experience now by toggling together websites and print, but it's not as fluid. I think it's that fluidity that the vook is striving for. Here's to one more step in a good direction as digital publications continue to mature.