DRM : my opinion

DRM or Digital Rights Management it's a technology which give content providers control over redistribution and acceses to material. It used by publishers ( or copyright owners) to control access to material. I think that it's necessary for copyright holders to prevent unauthorized duplication. It can affect pirate media but finally they always find a solution.
While digital rights management is most commonly used by the entertainment industry (films and recording), it has found use in other media as well. Many online music stores, such as Apple’s i Tunes Store , as well as certain e-books producers, have adopted various DRM schemes in recent times
DRM has been used by organizations such as the British Library in its secure electronic delivery service to permit worldwide access to substantial numbers of rare (and in many cases unique).