Marie Turek, product manager, e-books and Mendeley at SwetsThere can be quite a bit of variety between publishers, and restrictions in functionality vary enormously. Some suppliers have no DRM but some really restrict it. For some aggregators, DRM is almost on a title-by-title basis. While they’d like to give the illusion of one DRM for all, they are separate contracts and this might not be totally obvious to the end user.