I am also looking for more information on DRM.
Digital Rights Management encrypts your ebook so it cannot be decompiled or read on another device. In other words, it protects it like a lock. Nook and B&N applications can read it, so if a customer purchased a DRM ebook and they’re logged into their device or application on their computer, they can read the (their) ebook.
If you elect not to have DRM, they can send your ebook to a friend via email and that friend can read it on whatever reading device they have. Or they can resell your ebook on another website under their name. Or college students – so pesky, aren’t they? – can post it on their website and anyone can download it for free.
Obviously, those are worst case scenarios. If you created a file from a work by Charles Dickens and you want everyone to have it for free, no DRM is necessary, really. If you wrote it and you think it should have a copyright, that’s a pretty good indication you would prefer people, or college students, not share it with each other, and DRM is a good way to go.
I'm sure there are other opinions about it, though.
Thanks for clarifying. That helped a lot.