There are also a few big specific issues that come up in music a lot, like use of music in advertising. Musicians generally either: 1) don't want their music to be used in advertising, seeing it as cheapening it; or 2) want to be paid for it, seeing it as a major revenue stream. A CC-licensed work without an NC clause would allow use in TV ad jingles for free, which a large proportion of musicians don't like the idea of, even if they're otherwise pro-sharing.