I think everyone understands on a basic level how licensing works. That if you want to use somebody else's creation in your product, you need to get their permission and probably pay them some sort of fee or royalty. It's only fair, right?

Funny thing is that the original licensing agreement often doesn't cover everything that might happen. It's fairly common when a television series is released to DVD, the original music licensing no longer applies and the music needs to be re-licensed for the DVD release. And sometimes the studio in charge of the release opts to not re-license the music. I figure most of the time it's not something noticeable: generic free (or lower-cost) incidental music probably works just fine. And of course there's a whole industry of "sound alike" music out there for when you want something similar but don't want to fork out for the real thing.

In the case of the series Mission Hill it was a huge blow. Episodes of Mission Hill featured several songs in each episode by well-known artists. When it came to the DVD release, the studio didn't re-license any of the music. A huge loss, but for the most part not terminal Except for one episode that ends with the cast standing in the apartment, singing "Everybody Hurts" by R.E.M. Since the song rights weren't secured, it left the cast singing the lyrics with sort of a matching music track, but it certainly wasn't "Everybody Hurts".

This also happens in video games when they're re-released. I've found out that the re-release of Homeworld no longer has the Yes song of the same name for the final credit roll. Licensing reasons. And a shame, because that was one of the things that drew me to it. Of course all the people who have told me what a great game it is... that's a big factor too. But when you consider that Yes wrote the song specifically for the game, it seems like kind of a letdown that it couldn't be included in the re-release.

And it's not limited to music, either. The re-release of GTR2 that you can get on Steam... is missing the Ferrari and Porsche vehicles. Which strikes me as funny, since fully 70% of the NGT field is Porsche GT3s of one sort or another (and another 15% are probably Ferrari 360 Modenas). Perhaps Ferrari and Porsche wanted too much for their cars to appear in the game. Maybe whoever owns the rights to GTR2 didn't care to pay again. Whatever the reason, they aren't there. Although that doesn't mean it isn't a fairly easy process to put them back in... but it can't be officially sold with them included.