According to Billboard, YouTube is aiming to make its own Spotify-like subscription music service. There'll be a free streaming service (which, uh, should differentiate from free YouTube) and a premium tier that'll be like Google Music's All Access streaming service. Basically, every company wants their own music streaming service!
The streaming service is supposed to be made for mobile devices which, duh, since if you want to listen to YouTube on your computer you could just... YouTube it. Billboard describes the YouTube streaming service:
The free tier is likely to be unlimited, on-demand access to full tracks on all platforms, including mobile, said several people who have been briefed on the proposed service. In that sense, the paid tier is more of a "soft sell" as YouTube's primary goal is to continue to amass ears and eyes to its mobile platform to sell ads.
YouTube, which is already used to listen to music and watch music videos, is going to find itself in a potentially weird spot where it'll be asking users to pay for something they can get for free through YouTube and also asking for something that they might be already getting with its parent company Google. YouTube's official statement on the matter is below
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.