The current list of organizations, sorted by category:

Organization Category URL
Humane Society Animals
People for the Ethical Treatment of Animals Animals
World Wildlife Fund Animals
Big Brothers Big Sisters Children
Make-A-Wish foundation Children
World Vision Children
edX Education
Khan Academy Education
Manhattan Country School Education
National Outdoor Leadership School Education
Smithsonian Institute Education
TED Talks Education
Environmental Defense Fund Environment
Greenpeace Environment
National Wildlife Federation Environment
Sierra Club Environment
Sustainable Ocean Alliance Environment
Disabled American Veterans Health
Doctors Without Borders Health
Food and Water Watch Health
Open Medicine Foundation Health
Planned Parenthood Health
International Rescue Committee International
Kiva International
Red Cross International
United Nations Children’s Fund International
Watsi International
Associated Press News
Democracy Now News
National Public Radio News
American Civil Liberties Union Social Justice
Center for Social Justice Social Justice
Human Rights Watch Social Justice
National Organization for Women Social Justice
Center for Democracy and Technology Technology
Creative Commons Technology
Electronic Frontier Foundation Technology
One Laptop Per Child Technology