• by Erik Sass , Staff Writer @eriksass1, January 24, 2012

Wow, that’s a lot of cats doing funny stuff: YouTube visitors are watching an average of four billion videos per day, according to a post on the video platform’s blog, which represents an increase of 25% over eight months ago, double the volume in May 2010, and four times the volume in October 2009.

Meanwhile the volume of video content uploaded has increased to 60 hours per minute, up from 48 hours eight months ago. Here the growth curve goes from 10 hours per minute in January 2008 to 20 hours in May 2009, 24 hours in March 2010, then 35 hours in November 2010.

However, “only” three billion video views are monetized per week, which translates to just 10.7% of all videos viewed on the site. And it’s still a matter of speculation as to whether YouTube, purchased by Google for $1.65 billion in 2006, is actually profitable.

According to one estimate and forecast issued by Citi analyst Mark Mahaney last year, total revenues from YouTube will rise from $825 million in 2010 to $1.3 billion in 2011 and $1.7 billion in 2012. But it’s not clear how much of this goes to server costs -- considering the volume of video noted above, I will guess it’s not insignificant.

Still, the huge volume of traffic may make all these questions moot. It’s entirely possible that Google has never really cared whether YouTube is profitable or not, as long as it continues to enjoy near- total dominance in online video, ensuring that Google maintains control of this critical content category. Among other things, it provides a big lever for Google to wedge its way into social media; deeper integration of YouTube and Google+ can’t be too far away.