YouTube is a huge hit with users but it's "not a business," says The Economist. "Advertisers, by and large, will not touch user-generated content with a barge pole," the magazine says. "No brand wants to be near it." Rivals have tried to make online video pay, using all sorts of business models, but Hulu seems to have found the magic formula: Professional production, streamed video, free content, short ads. In fact, its ad inventory is sold out.