YouTube remains the largest streaming music service worldwide by far, and its growth rate is even larger than that of rivals like Spotify. YouTube also plans to launch a new music streaming service this fall, with a paid tier.

Everyone's talking about music streaming these days. With Apple throwing its hat into the game with the recent launch of its new Apple Music streaming service, media comparisons between Apple's new offering and those of its rivals like Spotify, Pandora and Tidal are ubiquitous. The one service, however, that often goes unmentioned in many of the latest news stories is actually the largest music streaming service in the world, and that's YouTube.

In the first half of 2015, 57 percent of the total 135.2 billion total streams worldwide were served by YouTube. The growth rate for YouTube streams is a staggering 109.2 percent, way ahead of competitors like Spotify, Rdio and Rhapsody, which still achieved a healthy growth rate of 79.2 percent. These statistics of course don't include the new Apple Music streaming service, which was just introduced, so it will be interesting to see if Apple's service is really the game changer the company is betting on.

The most obvious reason why YouTube remains by far the most popular streaming service is that it doesn't cost anything — the service is completely ad-supported. Spotify and Pandora have free ad-supported tiers as well, but another point in YouTube's favor is the content and availability of tracks. Listeners can find just about every song in existence on the channel, as users upload many of the songs, whereas competing streaming services are limited to the labels and artists with which they have contractual agreements.

Many listeners also use YouTube with a conversion tool from which they can create their own digital files of songs for their permanent library. It's also easier to work around YouTube ads with ad blockers like Adblock Plus, which doesn't work on other streaming services.

YouTube is not resting on its laurels, however, and is planning to introduce an additional streaming service sometime this fall called YouTube Music Key. Though details are sketchy, it is expected that the service will include both free and paid tiers.

Photo: Rego Korosi | Flickr