Ten years ago, few imagined that by decade's end, people would be reading novels on cell phones. A lot has changed in the book world. "Over the last couple of years, I've really noticed if I sit down with a book, after a few paragraphs, I'll say, 'You know, where's the links? Where's the e-mail? Where's all the stuff going on?' " says writer Nicholas Carr. "And it's kind of sad."