YouTube Close to Launching Subscription Music Service?

According to Billboard, YouTube is preparing to launch a premium on-demand music service. The company declined to comment, as it does every time this rumor pops up.
The service, designed with mobile listening in mind, will have a free component and a premium tier that offers unlimited access to a full catalog of tracks similar to what's already available via YouTube's parent company, Google Inc., via its All Access subscription music service. Premium features would include the ability to cache music for offline listening and removing ads.