From the Official YouTube blog:
When YouTube’s site first launched in May 2005, we never could have imagined the endless ways in which you would inspire, inform and entertain us every day.
Today, more than 100 hours of video are uploaded to YouTube every minute. That’s more than four days of video uploaded each minute! Every month, more than 1 billion people come to YouTube to access news, answer questions and have a little fun. That’s almost one out of every two people on the Internet.
All of which suggests that YouTube was a very smart investment for Google. Better, I suspect, than the $1.1 billion that Yahoo is about to pay for Tumblr.