My friend Beat has put up an interesting post about digital libraries, the poorness of current interfaces, and how 3D interfaces might improve them. I started composing a response in email, but it ended up rather long winded, so I thought it belonged here as well.
Of all the options Beat lists, I think the Google Glasses wall of books is the most interesting. I'm looking forward to the various digital overlays those things will provide to real life.
There's something missing, though, I think, with 3D interfaces for bookshelves (and 2D bookshelf interfaces). They're replicating interfaces defined by the hindrances caused by the physicality of books. I use Delicious Library to keep track of my paper books, and while it has the ubiquitous bookshelf interface, the interface I use is the database interface - looking like the old iTunes - basically, a list of all my books, with columns for title, author, genre, and so on. The bookshelf interface is too cumbersome. Fundamentally, I think the bookshelf itself is a bad interface. Literature isn't a linear space, but bookshelves are.
Basically, there are too many books in a collection for any linear interface to be helpful. 3D interfaces with shelves are just a slightly fancier way of presenting your books in a one-dimensional list with a single sorting algorithm. They way I see future digital libraries going include:
The loss of length limits - a novel currently needs to be between 150 and 1200 pages - any more and it gets expensive to print, any less and it's not a novel and won't sell. I'd like to have my short stories and novels all sitting in the same repository, without the short stories needing to be bound into anthologies. Charles Stross explains the current limitations well on his blog.
Interesting and powerful cross-linking and filtering - I want to be able to say:
"Find me stories by this author"
"Find stories that I'll like, based on books I previously enjoyed" (Amazon is doing this now, to an extent, and Delicious Library pulls this data into my local repository)
"Find me stories my friends enjoyed" (Goodreads does this well, but why isn't the data in my Calibre library?)
"Find me stories set in the same fictional world/continuity as this book"
"Find me stories where oak trees have a mystical significance"
"Find me stories written in a similar style as this one, but with more action"
"Find me stories set in 1930s South-East Asia where the European heroine is saddened by the plight of the native workers"
"Browse for stories by micro-genre, filtered for a certain level of seriousness"
Multiple searching and browsing interfaces - some folks will like the 2D or 3D bookshelf interface, but my children's children might not be familiar with that UI from real life. Tag clouds (2D and 3D), search result lists, and other interfaces that allow the viewing of more data, in a more structured way will be more useful.
The loss of book covers - these are another artifact of the current physical construction of books. I don't necessarily that the pictures will go away, but there might be multiple pictures, or a single picture without title/author text superimposed, or something else (perhaps a 3D scene from the book?). With the rise of comics in our collective literary consciousness, perhaps the line between novel and graphic novel will become more fluid.
Looser boundaries between texts - with the physical volume there is an sense of "oneness", or a text standing on its own. You might tie a series of these together into a trilogy (or a trilogy in five parts), but there are still those inherent boundaries. I remember the sense of wonder that Joe and I felt when we found a boxed set of Lord of the Rings in six books (for those of you who have only read it once or twice and don't remember the detail, each of the three books contains two "books" - Return of the King is books five and six, even in the big single-volume editions), which I think was partly because it violated (in a good way) that oneness of the three books in the series*. What we'll see in the digital future is more sets of stories that stand alone but form part of a something larger - the continuing adventures of a single character, or a set of characters, or the unfolding history of a town or a world; written by one author or many; in stories short and long and interlinked. We'll see short stories that fill out some minor plot point in another story, expanding and throwing light on the original story. We'll see parts of the same story from different perspectives. We'll see more borrowings of characters from one story into another. All of these things are happening now (in things like the Star Wars Extended Universe or various other franchises), but it will become more normal, more complicated and diffuse, and more accepted outside "genre" fiction. This is exactly the sort of thing that will break the "book" and "bookshelf" model of fiction.
Another problem with 3D interfaces to libraries (or 3D anything, for that matter), is that you only end up with slightly more room to move than in a 2D space. Some interesting ways of accessing information are inherently multi-dimensional (as an example, the range of questions I would like to ask above can be seen as making queries into a highly multi-dimensional data structure). Three dimensional interfaces as they stand today are mostly just fancy ways of viewing one- or two-dimensional data while using an expensive graphics cards. If our best real world interface for cataloging books is the bookshelf (a 1-dimensional filing system), how should a 3D virtual interface improve on that?
Lastly, to fit enough stuff into a 3D space, you really want to use a hyperbolic space, rather than 3D space (I couldn't find a really good visualisation of it, but here's a start). You can just fit more stuff into smaller distances that way - so you can create more powerful cross-linking of concepts in the space. I don't think this will take off in a big way until people have had more experience adapting to virtual worlds, so give it a (human) generation or two.
It's interesting food for thought, though. One of the exciting things about this is that we're at a point where we are heading into an unknown future, and any of a hundred guesses about how this will turn out are likely to be true.
* "You have to get this for Joe for Christmas," I said to his girlfriend at the time. She replied "What for? He already has a copy of Lord of the Rings". Says I, "No, trust me on this". A few weeks later she thanked me for how well chosen a present it was.
