DRM does nothing to stop piracy, the folks who crack DRM schemes love the challenge of cracking new DRMs and do so simply because they either hate DRM or love breaking restraints.
What DRM DOES do is to turn off customers who would otherwise be interested in your product. If you have a device which is not compatible with the DRM scheme being used or are worried about the company that supports the DRM going out of business then you will not buy the DRMed books for fear of those books being unusable in the future. I have worked in the medical field and in education for years and use some pretty narrowly marketed reference books, books focused on a very small and select customer base and these books are mostly all DRM free BECAUSE there is such a small market. If your target audience is a few hundred sports medicince docs then the chances of those books being pirated is MUCH smaller than a book on the best sellers lists.
DRM is not the answer to pirating, it does not stop pirating at all. DRM is like a cheap lock, it will not stop someone who really wants to pirate the book because there are so many ways around every DRM. This has been shown to be the case over and over again, DRM is not difficult to circumvent and it doesn't endear you to new customers who just want to be able to use their books on any device that they have or may ever have.
Last edited by jabberwock_11; 11-02-2012 at 10:52 PM.