Since the era of fuzzy sleeping cat videos, YouTube's creator base has grown up and gone pro. There are over 8,000 YouTube stars with over a half million subscribers—they're among the million creators that share ad revenue with YouTube. (YouTube creators also have the option of selling subscriptions, but nearly all opt for an ad-supported model).
YouTube has also created a vibrant ecosystem of content networks that foster, promote, and cash in on YouTube creators—Maker Studios was bought by Disney for $500 million, and Dreamworks Animation is paying as much as $117 million for teen-oriented Awesomeness TV. And it's not just content companies that are profiting from YouTube's platform: Ad tech company Zefr, which supports brands and content owners on the platform, has raised over $60 million.
The anniversary of Google's purchase of YouTube comes just the day after YouTube made its biggest-yet move into a new business model, a subscription business.
Next week it's starting to roll out "YouTube Music Key," which will cost $9.99 a month for ad-free music and videos, with the ability to listen offline as well as online. It's starting as an invite-only beta service, which will be free for the first six months, followed by a promotional lifetime price of $7.99. Subscribers to the new YouTube service will get free access to Google Play Music, which also costs $9.99, for access to 30 million songs. It's a bold move by CEO Susan Wojcicki, who took the helm in February, to test a totally new model, and to see if consumers will be willing to pay a company from which they're used to getting everything for free.
Read MoreHalf of YouTube's traffic is now mobile