Ben Rattray knows that revolution does not always happen spontaneously. The 31-year-old entrepreneur rattles off a list of populist actions over the past year: the consumer revolts against Bank of America’s and Verizon’s unpopular fees, a drive to enlist the San Francisco Giants to speak out against anti-gay bullying, a petition forcing the South African government to address the rape of lesbians. Each campaign won thousands of supporters, inflamed public opinion, and drew the ire of corporate executives and political leaders. Empowered consumers are forcing some of America’s largest corporations, from Apple to Bank of America, to make radical changes to their products or policies. The Washington woman is credited for starting a petition to get Bank of America to back off its proposal to charge a monthly debit-card fee. The bank abandoned its plan. But these were not impromptu rebellions that chanced upon success. They were carefully nurtured by Rattray’s fledgling company, a social media site called Change.org that has emerged as one of the most influential channels for activism in the country.