If you thought digital music was disruptive wait till you see what's in store for books. Here's one interesting piece on digital book lending, and another here. This library has wait times of over three weeks for some ebooks.
Should you be allowed to sell a digital song you downloaded? How about a book? Nerd alert: this one is heavy on economic mumbo-jumbo.
Good to know: you won't sink if you fall into lava.