Learn more about domains (.gov, .edu, etc.) below. http://youtu.be/ognOAlWvu0Q
More domain info: http://www.usg.edu/galileo/skills/unit07/internet07_08.phtml
.gov is automatically more reliable. With the other domains, you need to be sure information is accurate and not biased. .edu sites are great if they are part of research and instruction at a university. But, be careful. Student created websites can also be in the .edu domain.