It would be great if there was an ability to embed music from Spotify into Web Videos. Not actually adding the music in the video but when you play the video, Spotify will play the song in the background as if it was in the video. I believe that one of YouTube's biggest problems is that people use copyright protected songs in their videos. Using Spotify for the music in web videos would solve this issue.
In order for this to work there must come a basic music editing add-in for applications like Final Cut/Premiere/iMovie. Nothing complex just basic fade-in fade-out options. Artists will get some royalties through Spotify and people can use their favorite music in their videos. Seems like a win win to me.
In order to play the video correct people will have to have Spotify installed on their computer so this could boost the amount of Spotify users.
Changed back to "new idea" status - once this idea reaches 40+ kudos the Spotify staff will review it again and decide on a new status. ;)