Ed Felten has written an extensive report on the use of DRM on CDs. The report's conclusions are worthy of reproduction:
First, the design of DRM systems is driven strongly by the incentives of the content distributor and the DRM vendor, but these incentives are not always aligned. Where they differ, the DRM design will not necessarily serve the interests of copyright owners, not to mention artists.I tend to agree that non-transparent DRMs are a tremendous risk to the public. I am also highly sceptical that they work at all, those who are more likely to make copies will find it easier to circumvent the protection.
Second, DRM, even if backed by a major content distributor, can expose users to significant security and privacy risks. Incentives for aggressive platform building drive vendors toward spyware tactics that exacerbate these risks.
Third, there can be an inverse relation between the efficacy of DRM and the user’s ability to defend the computer from unrelated security and privacy risks. The user’s best defense is rooted in understanding and controlling which software is installed on the computer, but many DRM systems rely on undermining the user’s understanding and control.
Fourth, CD DRM systems are mostly ineffective at controlling uses of content. Major increases in complexity have not increased their effectiveness over that of early schemes, and may in fact have made things worse by creating more avenues for attack. We think it unlikely that future CD DRM systems will do better.
Fifth, the design of DRM systems is only weakly connected to the contours of copyright law. The systems make no pretense of enforcing copyright law as written, but instead seek to enforce rules dictated by the label’s and vendor’s business models. These rules, and the technologies that try to enforce them, implicate other public policy concerns, such as privacy and security.