Downloadable Album Costs More Than CD On Amazon

Rob points out a pricing quirk on an album he’s after, noting that the physical CD is considerably cheaper than the digital download.

A little freaked out, he writes:

Forget about Target… Amazon is even worse with their pricing (note: I LOVE Amazon and I’m sure this has to do with licensing but still…wtf!?!). I was looking to get the new OAR CD, “Rain or Shine.” I was going to buy the CD when I thought to myself, “Wait…I’ll just get the download instead,” since I’m impatient. Well the PHYSICAL CD is $13.99 but the digital (NOT PHYSICAL) album is $20.99! Less work for them and yet they charge more! Ahhh! Amazon…please don’t turn evil like everyone else!

With an untold amount of CDs and their digital counterparts for sale on the site, there are probably several instances of this quirk. Does anyone have an explanation for it?