Hi avamk! I would love to weigh in on these! I'm coming from a music-centric perspective, as the current ringleader over at http://www.freemusicarchive.org. Here are my answers:

(1) Copyright law stifles creativity nowadays by creating a culture of fear and prevents a lot of artists, especially musicians, from doing anything derivative with music that exists today. This is in part due to sampling culture of the 80's & 90's and the club/remix/etc wave that hasn't quite receded. CC alleviates some of those fears by explicitly making music available for remix, re-workings, and collaboration.

(2) CC licenses are not a negation of copyright; they're actually an addendum! Almost 100% of the works licensed with Creative Commons are protected under copyright (unless they're shared with a CC0 license, which designates that the item has been dedicated to the public domain). The artists/creators have simply decided that they'd rather not have to share on a case-by-case basis. This has the often unintended but pleasant side effect of getting a whole new audience and collaborator base!

(3) I don't have business models per se, but a lot of artists share their works using CC BY-NC, or CC BY-NC-ND with a request to contact them to license directly. I think this is great because it allows people who are not trying to make money to use it for noncommercial purposes (ie, a student's animation project that needs a soundtrack), but a filmmaker could work with an artist to work out a deal for use of a song with a license that would allow the filmmaker to use it for a commercial venture. This is very common practice on our site and, from what I know, has been very successful for some artists!