Nice article at the BBC. Best bit:
"Nearly a third of [people] who had albums by the Red Hot Chili Peppers said it grew more valuable to them as time went on.
But over 80% of Britney Spears album owners said they had grown tired of her records."
This "phenomenon" was well described by Dance DJs in the 90s who knew full well just about every single they ever saw was probably a one-hit wonder, but more importantly had a very short shelf life, becomming unplayable just weeks after release.
Once again, we see that crap music = low sales. If you get to try before you buy, then you don't buy crap. Decent music still has (and always will have) intrinsic value, and so will make sales. This report veils this by simplistically suggesting that downloading alone affects sales. If every record store had every album on the "listening post" (as indeed they should) you'd end up buying a lot less albums that you got home and didn't think much of. Cut out the dross, and everyone's CD collection would be smaller, but of significantly higher quality.