The rumor mill's been churning out tales of a forthcoming YouTube music streaming service for months now, and today Billboard published a new story with a startling amount of detail about it. According to unnamed sources, YouTube's working on an on-demand music service with both free and paid tiers. Apparently, the ad-supported free version will provide unlimited, on-demand access to a whole host of tracks on any device, thanks to the licensing agreements Google struck for its Google Play All Access music service. Aside from the obvious -- removing ads from the equation -- it's unclear what folks will get for their money should they choose to opt for the paid version.

This new rumor is lended credence when considered in light of last month's revelation that YouTube will be offering offline access to content next month -- a feature that'll likely be expected from consumers who have grown accustomed to such things from the likes of Spotify, Rhapsody and other subscription music services. According to Billboard, YouTube's service has yet to receive a release date, and given how long these rumors have been floating around, it seems reasonable to expect that we won't see the new service anytime soon. For its part, when we contacted YouTube for comment on this story, we, quite naturally, got the same reply as Billboard did:

We're always working on new and better ways for people to enjoy YouTube content across all screens, and on giving partners more opportunities to reach their fans. However, we have nothing to announce at this time.