My theory - heavily influenced by Chris Anderson, author of The Long Tail articles, books and blog, is that the digital age may be the death of the blockbuster book culture we've been experiencing for the past 50 years. The blockbuster complex (first coined by Thomas Whiteside in 1981), beloved of booksellers and big publishers who push those hugely popular books by the Dan Browns, Tom Clancys and Stephenie Meyers, may be flirting a war with the infinite choice provided by the Internet.
Such diveristy in choice didn't just surface with the Internet. The blockbuster complex's rise in the book market was due in part to commercial booksellers and book retailers like Borders, and Barnes and Noble. These international book superstores can easily stock 100,000 titles in store - much more than your average back-alley bookshop.
The digital age initiated the publishing industry to the e-book and online retail: 160 publishers currently have Internet publishing businesses that produce, publish, distribute and sell e-books. As of 2001, Cope and Ziguras (two RMIT professors) counted over 10,000 publications for sale by download via Internet publishers. Just imagine how many there are now. There are books for sale in store, online, e-books, Print on Demand books, e-bay books, book-swapping forums, books coming out the wahzoo. Naturally, consumers had more choice, developed a taste for their raison d'etre and now want more.
Chris Anderson's theory is that the blockbuster model which supports the ‘head’ of the market, where consumers rapidly buy millions of copies of the same book, is being balanced with the ‘Long Tail’ of consumers that purchase a large of number of ‘non-hit’ items over a longer period of time. Online retail giants like Amazon - unrestricted by the physical space of a bookstore - can market billions of different titles at once. Amazon has a total inventory of 3.7 million book titles and compared to a typical Borders or Barnes and Noble of 100,000 titles, makes it easy to find those books that can't be found anywhere else. Here is a dinosaur chart from Edgwater Technology Weblog to demonstrate the Long Tail:

Amazon founder Jeff Bezos once said his goal was: "to make every book available – the good, the bad, and the ugly." The Web has enabled us to see the light at the end of the blockbuster tunnel - the good among the bad and the ugly. I love ye olde bookstore, but for science fiction and fantasy readers like me, the online book market has opened up new vistas. I am going see if I can order Patrick Rothfuss' new novel - which comes out in Australian bookstores in December - off Amazon. Don't damn me for not supporting Australian publishers. I need it. I'm a niche market.
If you're interested in the Long Tail theory you can read Chris Anderson's Blog on Wired.