Nicholas Carr on e-books, and the new impermanence of text:
Books That Are Never Done Being Written

…as is often the case with digitization, the boon carries a bane. The ability to alter the contents of a book will be easy to abuse. School boards may come to exert even greater influence over what students read. They’ll be able to edit textbooks that don’t fit with local biases. Authoritarian governments will be able to tweak books to suit their political interests. And the edits can ripple backward. Because e-readers connect to the Internet, the works they contain can be revised remotely, just as software programs are updated today. Movable text makes a lousy preservative.