When the world's major consumer goods companies hang on your every word, you know you are in a position to define power. But Wal-Mart's Leslie Dach, hired in 2006 from its PR firm Edelman, has worked hard to alter the shopping giant's reputation, positioning it as a responsible global citizen that can rely on some of its 2.1 million employees to be its most loyal advocates on social media. With reputation increasingly forged on social networks, that's a formidable level ...