As their site explains:
In order to unite the public, media, and our political leaders behind the 350 goal, we're harnessing the power of the internet to coordinate a planetary day of action on October 24, 2009.Other similar sites include the Global Footprint Network with the premise that as the world's biggest environmental impacting species, human beings, need to understand the impact they are making in order to see the outcome. Using interactive quizzes and imagery this website is enlightening to say the least.