Copyright and Full Albums on YouTube

In the last year or so, a lot of full albums of recorded works have appeared and stayed up over at YouTube. Just to pick a few examples among thousands, maybe you want to listen to The Beatles’ Sgt Pepper’s Lonely Hearts Club Band, John Coltrane’s A Love Supreme, the Beastie Boys’s Paul’s Boutique, Pink Floyd’s Dark Side of the Moon, Miles Davis’s Kind of Blue, or Tupac Shakur’s All Eyez On Me. They’re all there for the listening over at YouTube, and they’ve been posted there for a while (on average, about half a year for the albums I have listed). And none of them appear to have been posted by the copyright holders.

I’m curious about why they’re up, though. I would think that all of these albums are still under copyright. They all sell pretty well, as far as I can tell: Dark Side of the Moon is #177 in Amazon music sales right now, and Kind of Blue is #203. It wouldn’t be hard for the copyright owners to have YouTube take them down. So why are these and many other albums still available? Is there a glitch in the copyright laws that makes it plausible that these albums are not infringing, perhaps related to copyright laws outside the United States? Alternatively, are copyright owners giving up and not trying to have their content removed for older works, figuring that enforcing their legal rights isn’t worth it? Or have copyright owners decided that it is to their advantage to have the copies of full albums available, perhaps on the theory that access to poor-audio versions at Youtube might create exposure that would spur legit sales of CDs or MP3s? (That worked with me for Keith Jarrett’s Live at the Blue Note, actually — just ordered.) Or is the explanation some mixture of these reasons, or some other reasons?

I’m sure some readers must know, and I hope they might shed some light on this in the comment thread.

UPDATE: Thanks to commenters, here’s the answer: In August 2011, YouTube and music publishers reached a settlement that allows the publishers to receive royalties and a share of ad revenues when someone uploads an infringing musical work. Content owners tell YouTube how they want to respond to users uploading their works, a system called ContentID, and they can opt to let the videos stay up. A short explanation is here:

Fascinating.