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The sites have a large probability of failure then Scott. This is reality. Either the users host the files , or the sites will be centralized (same as google, stickam,justin.tv, imeem, etc) . Remember Kazaa, Limewire? The users hosted the files them self. This is not new technology. P2P filesharing has been around for a long time now.

as a professional social media marketer I'm thinking long term, I'm thinking mass adoption