Digital rights management, or DRM, is a set of technologies used to control piracy. An example is the “Fairplay” system that Apple used until recently on most songs sold in its iTunes store. Fairplay was a set of digital locks that blocked certain uses – for example, a song could be played only on up to five authorized computers. As you might imagine, DRM has been controversial, at least among some people who want to make uses of content they’ve purchased – like making a back-up copy, or copying small portions of a work for fair use purposes. Music DRM once involved the installation – without users’ knowledge -- of a particularly malicious bit of software that modified, and sometimes broke, the operating systems of customers’ computers. That strategy imploded amidst government investigations, class-action lawsuits, and a storm of terrible publicity. In contrast, e-book DRM has been nowhere near as controversial, or ineffective. Still, the fact remains that many DRM-haters exist.