I came across this article by Joe Konrath and thought it was an interesting take on the future of eBooks. It's fairly intricate and deserves a full read, but basically speaks to what Konrath calls "active eBooks" involving live chats and discussions with other readers, author commentary, and dynamic books where content can be added and changed at a moment's notice.
While I don't necessarily agree with all of it - the hypothetical scenario he describes seems to be fairly intensive for all but the most "classic" or popular of books, especially for people who are looking for a purely entertaining read and aren't particularly interested in critical discussion or analysis - it isn't so much a look at what will happen but rather what could happen. Giving these options to eBook readers makes the format more than just "books, but electronic!" and will certainly prove to be a more disruptive innovation. Plus, anything that involves giving consumers more value and more reasons to buy is definitely a plus in my book (or eBook...).
His post was from a year ago, and we haven't quite reached what he's discussing yet. However, I can't wait to see if something like this takes off and how well it's utilized by publishers, authors, and readers.