There’s been rumors for months that Google is planning on launching a subscription music service on YouTube, and now the rumor mill is saying the search giant plans to name the service “YouTube Music Key.”The service will “offer ad-free playback, the ability to save songs and videos for offline listening, and an audio-only interface for when you’re multitasking or want to have music on in the background, all for $9.99 per month,” reports The Verge.Google is simultaneously planning to relaunch the subscription music service it has on Google Play as Google Play Music Key, and it looks like the $9.99 subscription fee will allow subscribers to have access to both services.Meanwhile, one of Music Key’s main competitors is expanding its subscription music offerings to Canada. Spotify launched an invitation-only preview of the Canadian site, with plans to open it up to all users soon.Spotify allows subscribers to build playlists from its database of 20 million songs. The ad-free version costs $9.99 a month for US audiences (no firm word on the cost in Canada, but its likely to be comparable).According to The Globe and Mail, the Canadian market might be more alluring to companies since a new ruling says streaming music services would have to pay about 10.2 cents in royalties for every 1,000 plays, significantly lower than the $1-$2.30 that the Canadian music industry had demanded.With all this activity, its easy to assume that streaming, subscription-based music is the new booming market, but keep in mind, it’s still the most difficult digital paid content niche to make profitable.