Members of the Twitterati might be useful in spreading a new kind of American diplomacy abroad. "We need to use soft power in hard places," says one of America's top diplomats, and social media is just the way to apply it. [...] He's (Undersecretary Stengel) looking to the country's artists, musicians, athletes and citizens abroad to be the engines of discourse, amplified and distributed through the power of the Internet, mobile phones and social networks.