A propos to the conversation in general and photon's concerns in particular, Columbia law students provide a summary of some of the legal issues involved when you "buy" a book for your Sony e-reader or Amazon Kindle. It's all based on US law and has little applicability to the state of Canadian affairs but it does give you a sense for the DRM concerns many have.
http://gizmodo.com/369235/amazon-kin...o-longer-yours