Cory Doctorow has a must-read article for anyone interested in copyrights and DRM (which officially stands for Digital Rights Management, but is more like Digital Restrictions Management).
He points out something that should be obvious to everyone who owns a computer: DRM makes our computers less secure. DRM treats you (the owner of a computer) as the enemy, and whose rights must be limited. DRM is like a virus, because it takes away control of your computer from you. It controls whether you can play a piece of media, or copy it (including making a backup). Even worse, real viruses can then piggyback on DRM, which is exactly what has happened.
But what really screams insanity is the host of laws that have been foisted upon us in order to enforce DRM. In the US, this is the DMCA. The DMCA is unconstitutional because it violates free speech. It is also unconstitutional because it allows companies to criminalize something that is (and should be) legal, with no protections for individual rights.
Ironically, the DMCA also has the effect of making your computer less secure. Because researchers are prohibited from talking about flaws in digital security, the process required to improve security is compromised. We have already seen several cases where security researchers knew about computer vulnerabilities, but were afraid to tell people about them so that those vulnerabilities could be fixed because the DMCA made that illegal. Ironically, one of these cases was a vulnerability caused by DRM itself.