This idea has been set to Not Right Now for quite a while now. In the meantime we've ran different tests with this feature, including matching the ad background music to the user Library, but regrettably this wasn't feasible given the variety of available ads.
We've discussed this internally once more and as it's not something that we plan on implementing in the foreseeable future, will be setting the status to closed, to match our new Idea Exchange statuses. If we do have any new information to share, rest assured we'll check back in here with a new status.
More info on why your idea has been closed can be found here.