It’s always worked both ways (video marketing the song/song marketing the video) – the video networks (to the extent they still play videos) program videos largely based on radio airplay of song. The difference is the major labels, in moving to the web, decided it made more sense to participate directly in the business being built around the content (thru per stream royalties and/or ad revenue share). This was the case under the old Warner deal – what’s changed here is who’s selling the ads/setting the prices (and of course the rev split). The majors haven’t been happy with the revenues YouTube has been able to generate so have taking the sales function out of the hands of YouTube. This is similar to the Vevo and Hulu models in that the content owner controls the ad inventory around the content (regardless of where it’s distributed). This (theoretically) addresses the consumer demand for ubiquitous distribution of content and the content owners’ interest in creating a scarcity of ad inventory (something that isn’t achieved under the model of licensing one’s content to multiple parties who are each free to sell advertising around it).