The new Microsoft Zune player (their soi-disant "iPod Killer") applies DRM to all the files you move onto it, even the Creative Commons-licened music. The problem is that CC licenses prohibit this. What's more, CC licenses are machine-readable and could, theoretically, be detected by Microsoft, if they cared enough about copyright to ensure that they were adhering to the license policies set out by creators.
There currently isn't a way to sniff out what you are sending, so we wrap it all up in DRM. We can't tell if you are sending a song from a known band or your own home recording so we default to the safety of encoding.
(Thanks, Christian!)
Update: More on Medioloper
