I recently discovered the Care2 website, and it's very interesting.
On the Care2 website you earn credits by doing things like commenting on polls and news articles, signing and starting petitions, and completing the daily action and then redeem them for "gifts that make the world a better place." Overall I think it's a cool website and worth checking out.
Here's one thing on their website that really made we go WOW! I had never heard of the Butterfly Effect, but I will definitely be researching it now.
"Care2's mission is to help people make the world a better place.
The butterflies on our logo were inspired by a concept in physics that became popularly known as the "butterfly effect", where one small change can cause a chain of events leading to large-scale phenomena.*
* The "Butterfly Effect" reference is to a story about the flap of a butterfly's wings in the Brazilian rain forest, that moves the air, that redirects the breeze, that alters the wind, and eventually leads to a hurricane moving up the east coast of America. A small change that results in an incredible outcome."-http://www.care2.com/aboutus/logo.html