Great idea, however the implementation is going to take a while.
Like what a few others have said, Youtube has been the most successful at what it's doing and no one has surpassed even half of what youtube already has. And it will only continue to grow. The only thing we can do is hope that another site which shares their purpose with youtube will grow to be its rival. Which I doubt will happen in a very long time, even I use youtube, quite frankly. So it's possible, however the real question is "WHEN".

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Globalization is the key to success. We have it, we just don't know what door it unlocks.