BoingBoing and others covered a recent story out of Europe: Deutsche Telekom's Musicload service (one of the largest digital music stores in Europe) says 75% of customer service calls were about DRM problems. Musicload has come out strongly against DRM:
According to Musicload, DRM "makes the use of music quite difficult and hinders the development of a mass-market for legal downloads." The lack of interoperability is unfair to customers and prevents true competition between music services, in other words.
So, what does billions of dollars in DRM get you? Lots of unhappy customers calling you with problems!
Interestingly, ArsTechnica reports that artists selling without DRM on Musicload saw sales increase by 40%.