More than one million Americans accepted the Tide Coldwater challenge, washing their clothes in cold water to save money and energy while still achieving deep cleaning for their laundry. The web-based challenge created by Tide Coldwater and the Alliance to Save Energy could save the U.S. up to $63 million, according to company executives. The site encouraged consumers to take the challenge and enabled them to track how they spread the word about the challenge to friends. Tide Coldwater donated $...