Amazon has been granted a patent for adding what is described as “DVD extras” to ebooks, suggesting that in the same way as movies were enhanced via special features like cast and crew interviews, documentary footage and behind the scenes information, books could be similarly added to.
Video isn't something that the average ebook reader is built around of course, with their eInk screens. However, pictures are no problem, likewise are supplemental materials. As Wired points out, how about a map of the region in the world the story is taking place? Or an illustration of one of the main characters drawn by your friend?
Or have this pop up to get you in the mood – *WARNING VERY NSFW*[yframe url='http://www.youtube.com/watch?v=xbEhByk4Icg']
Extra storylines could be brought in from other mediums, showing the transformation of certain characters – perhaps a certain Game of Thrones character into the poor retch known as “Reek,” for example. In that particular epic, there is a lot of background information that isn't included in the books or TV show, so there's lots of potential for appendicesed information to be brought forward and contextualised through a link, instead of being bundled at the end.
Likewise the Lord of the Rings has a lot of extra information that could be included earlier in the books.
Now though with Amazon owning the patent, good luck finding those sorts of features on anything not published in the Kindle format.
KitGuru Says: I like this idea. I was always a fan of a book with a map printed inside the front cover. That was somewhat lost with ebooks, but now you can have that map available at the touch of a button.