4,000,000,000 is 1,000 times four million. Let's say there are four million YouTube videos out there. So each of them are being watched for 1,000 hours each. But each video is only five minutes long. So that's 12,000 views per video.
12,000 views - that's not a whole lot. It's not 12 million. In TV lingo, 12,000 views are not a hit. But four billion hours worth of video watching is a lot of video watching.
This is fragmentation. This is crowd power. A hit might be harder to accomplish. But crowd needs are being met.
We Now Watch 4 Billion Hours of YouTube Videos Per Month
YouTube users upload 72 hours of content to the site every minute. In fall of 2008, users were uploading just 10 hours of video each minute