YouTube, the world's most popular online video-sharing site, is showing inexorable growth. Google announced that people watch 4 billion videos on YouTube per day. And every minute, 60 hours of videos are getting uploaded. To celebrate this achievement, YouTube has launched a special comic-cartoony site (http://www.onehourpersecond.com/) to show what one hour per second means in various situation.

For example, in 1.5 seconds of uploads to YouTube, the International Space Station completes one orbit of the earth, or in 5 minutes, 36 seconds of uploads to YouTube, two weeks of video is uploaded, and Tillman the Bulldog travels a combined 192 miles on his skateboard.

Since the dawn of YouTube, we’ve been sharing the hours of video you upload every minute. In 2007 we started at six hours, then in 2010 we were at 24 hours, then 35, then 48, and now...60 hours of video every minute, an increase of more than 30 percent in the last eight months. In other words, you’re uploading one hour of video to YouTube every second. Tick, tock, tick, tock — that’s 4 hours right there! announced Google on its YouTube blog.

Now with 4 billion videos watched per day, it is like almost half of the world population is watching one YouTube video daily. Indeed it seems YouTubers enjoy consuming video as much as they enjoy uploading their content.

YouTube, whose slogan is Broadcast Yourself, has become biggest video sharing site based on user-generated video contents including movie clip, and TV clip and music-video as well as amateur contents like video blogging and short original videos.

Google's push for YouTube to be extended into smartphone and television from PCs has played a pivotal role in YouTibe's amazing growth, according to Reuters.

However, according to Google, not all videos are profitable. Only 3 billion videos a week are monetized. But YouTube plans to increase professional-level contents of movie and TV by partnering with various media corporations to generate more profits.

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