Amazon has the ability to delete from your Kindle books that you have purchased.
Consider the legal difference between purchasing a physical book and buying one for your Kindle. When you walk into your local Barnes & Noble to pick up a paperback of Animal Farm, the store doesn't force you to sign a contract limiting your rights. If the Barnes & Noble later realizes that it accidentally sold you a bootlegged copy, it can't compel you to give up the book—after all, it's your property. The rules are completely different online. When you buy a Kindle a book, you're implicitly agreeing to Amazon's Kindle terms of service. The contract gives the company "the right to modify, suspend, or discontinue the Service at any time, and Amazon will not be liable to you should it exercise such right." In Amazon's view, the books you buy aren't your property—they're part of a "service," and Amazon maintains complete control of that service at all times. Amazon has similar terms covering downloadable movies and TV shows, as does Apple for stuff you buy from iTunes.
The power to delete your books, movies, and music remotely is a power no one should have. Here's one way around this: Don't buy a Kindle until Amazon updates its terms of service to prohibit remote deletions. Even better, the company ought to remove the technical capability to do so, making such a mass evisceration impossible in the event that a government compels it.
Ironically, George Orwell's 1984 was one of the books deleted.
I find this scary. It's not so far-fetched, either, or something that might happen in some dark version of the future. Imagine going to China with your Kindle and the government insists Amazon delete all copies of prohibited books on all Kindles in China. Zap.
"Immersion in the life of the world, a willingness to be inhabited by and to speak for others, including those beyond the realm of the human, these are the practices not just of the bodhisattva but of the writer." --Jane Hirshfield