Does Criticism of Wal-Mart Effect Anything?

Today at the Washington Post:

Or consider the environmental behavior of U.S. companies at home. This used to be the classic case of politics leading business: For most of the past generation, regulators have forced environmental rules on grumbling corporations. But in the current debate on climate change, this order has reversed itself. Impatient companies are capping their own carbon emissions: Wal-Mart has promised to double the efficiency of its vehicle fleet and achieve a 30 percent cut in its stores' energy usage. Its motive is not complicated. Internet-enabled critics have assaulted Wal-Mart, and the firm's polling has suggested that 8 percent of shoppers have quit visiting its outlets because of its stance on social issues. An environmental makeover was essential to the brand.