This list is incomplete. If you are like me, curious, try reading some of these just to find out why they were banned in the past (some will be in the future as well).
I love my Kindle. I don't love the .azw format. I love buying ebooks and reading them on the Kindle. Since most ebooks are only $1 less than mass-market paperbacks, I tend to see them as "sharable". Amazon encrypts the .azw ebooks to a single Kindle. That keeps the books from being shared. At the moment, the decryption software does not handle Kindle 3 books. Thanks to BN.com, I can download ebooks in a much nicer format, specifically .epub. The tools to decrypt .epub books handle the encryption very well. If I am shelling out $6-$14 per book, I treat them like true physical books--I give them out to others. That seems to fall under the "fair use" idea. Don't I own the ebook once I have purchased it? When I buy a physical book I read it and pass it on to my coworkers and family. I will do that with ebooks too.