The device is still capable of tying personally identifiable information about you to the book, and remotely deleting or modifying it. There are no laws that I'm aware of that would keep Amazon, or any other company, from doing either of these things, or simply recording your behavior quietly, as the collected data awaits a sales opportunity or subpoena. Can't do this on a massive scale with physical books.
-doctorfrog
There are outlets other than b&n and amazon for purchasing non-drm books. And if one of them actually modified something on the device that you didn't purchase from them, that would be a very bad thing for them (and pretty stupid also, as most would have backups - or in the case of a couple of outlets you can re-download).
-wraith808
Which sites do you know of? I am always looking for some good non-drm sites to buy ebooks for my kindle.
-Josh
http://www.fictionwise.com (a shadow of their former self since b&n bought them... but still have multiformat non-drm books)
http://www.ereader.com (basically a different view of fictionwise.com in my experience)
http://www.fsand.com (science fiction and fantasy)
http://www.angryrobotstore.com/ (science fiction and fantasy - no kindle support, but they recommend using calibre to convert)
http://www.baen.com/ (one(?) of the only publishers that I know of to get on the non-drm ebook bandwagon - sci-fi and fantasy)
http://www.webscription.net (baen uses them for distribution, though they have publishers other than baen)
http://www.smashwords.com/ (indie authors and publishers)
MobileRead Wiki also has a list, though I haven't tried any of them not listed above.