LATE last month, tens of thousands of runners who are registered for this year’s New York City Marathon got an e-mail from Mary Wittenberg, the president and chief executive of New York Road Runners.
Ms. Wittenberg wanted to introduce them to a person whom many had already heard of: the actor Edward Norton. But the words “Hollywood movie star” didn’t appear once in her message. Instead, she implored the runners to join a social networking Web site that Mr. Norton and three partners started in May that she says has the potential to revolutionize charitable giving. It’s called Crowdrise.com. [más…]