"It’s digital rights management, the coffee equivalent of Steve Jobs’ attempt to fill iPods only with music sold through iTunes."

What?? Not really. Keurig machines refuse to use anything other than a Keurig-brand K-Cup. The iPod always played non-DRMed music. It just wouldn't play music with DRM from other stores.

Any store willing to sell music without DRM is/was perfectly compatible with the iPod.