How??? Advertisers....I dont know why Youtube doesnt pay you for videos that you submit and become viral or very popular....Today a guy submitted a very popular invention that went viral i think he did it for fun...Now someone else is going to elaborate on it make hundreds of millions from it and say they didnt get their ideas from it and the person who invented didnt get a cent....Even if it didnt make it to an invention which i dont see why not it should had done to t he guiness world record and not even that...

Anyways there can be different kinds of Youtube...News youtubes, videos, etc...And there can be different types, like: India Youtube, China Youtube, Russia Youtube, Brazil Youtube, Europe Youtube, Africa Youtube, Gossip Youtube, Sci-Fi Youtube, etc....

And they make it happen thanks to advertisers, advertisers from all over the world...By this i mean: 1 minute of advertisers before they watch the video....Youtube advertisers is more like: 5 seconds of advertisement...

All you need is a Supercomputer to Store the video capacity....