When one considers the numbers and support that a site like YouTube receives, it's hard to imagine it not being a financial success. Sadly, the company has not made Google any profit yet.
The Wall Street Journal reports that YouTube received $4 billion in revenue in 2014. However, the finances aren't enough to cover all its costs. When you consider how much YouTube spends on creators and on streaming upgrades, it's unsurprising that YouTube that tends to "barely break even", according to one source on the inside.
WSJ notes that this is in part because of how difficult it is to make a profit from the teen/tween demographic. On top of that , the fact that the site is more of a video repository than a central content hub for many makes it hard to build a central profit system in.
Google hasn't made any profit off of YouTube since they acquired the video streaming service in 2006.
On top of that, other companies are getting into the video business, either as video hosting, as sources for popular creators or as creators themselves. YouTube has attempted to turn the site into more of a hub for content consumers before, but as WSJ notes, most of the attempts dried up rather quickly. In fact, YouTube has had to pay some of its creators bonuses to keep them around.
However, YouTube isn't finished. As Tubefilter notes, the video streaming service's recent decision to host NFL content and create a family-friendly app will help diversify their interests and expand the market. We won't know if these decisions were financially effective until 2015's revenue report.