YouTube is celebrating its seventh birthday, and as such, has revealed a fairly mindblowing statistic: YouTube users now upload 72 hours of video content to the site every minute. A year ago, that figure was "just" 48 hours every sixty seconds. Other interesting tidbits of note include the fact that 800,000,000 YouTube viewers watch over 3 billion hours of video each month, which equates to roughly 15 minutes per viewer. The site is, if you haven't noticed, a freaking juggernaut. Check the video after the break that celebrates seven years of YouTube, and feel free to leave your favorite YouTube videos in the comments.