http://about.usps.com/what-we-are-doing/green/welcome.htm for more information.
These Go Green (Forever®) stamps illustrate simple things we each can do every day to save the environment.
Go Green, a sheet of 16 stamps, is the Postal Service's social awareness issue for 2011. Award-winning animator, filmmaker, and illustrator Eli Noyes worked with Art Director Derry Noyes on his first stamp project, using a colorful, playful style to convey the message that every American can take simple actions to conserve energy and improve the environment. These Forever stamps are always equal in value to the current First-Class Mail one-ounce rate.