Sites for volunteers and volunteer-driven organizations

Volunteers support many non-profits, charities, causes, and people in various countries and walks of life. A volunteer is someone who does something normally classified as work for the sake of helping others rather than a paycheck, often while gaining valuable skills and life experience along the way. Virtually anyone can be a helpful volunteer, but people with specific skills or education like carpentry or medicine are priceless. This list contains the best sites relating to volunteers... primarily made up of sites where non-profits and volunteers can connect, people can find volunteer opportunities, or the sites of volunteer-driven organizations themselves. If one is missing please "add a site to this list" at the bottom left.