YouTube's perceived success

How successful is YouTube really? It's website generates 72 million pageviews per MONTH, and a 100 million videos are streamed every DAY. But where? And if it is not on www.youtube.com, how will they make money? Not this way probably... And if it's primarily (90%+?) on other websites, then how sustainable is their apparant success compared to services that are similar or even better? Everybody is writing about the success of YouTube while refering to YouTube as a destination website, but it isn't. At least not by the numbers you read everywhere....