Generally a web sites produced by an educational or governmental institution is are more reliable than personal web sites. Remember though that educational institutions often provide web space for their students, staff and faculty that are not vetted by the institution. Personal sites may be recognized by checking the URL for the use of a tilde (~) followed by a personal name, or the words "users," "members," "students," or "faculty." Whenever you come across a personal web site, investigate the author's credentials.
More information about domain codes:
Image: 1919 Cleveland Advocate article, "All We Want is Courage," Writes Local Boy "Over There." Courtesy of The African-American Experience in Ohio.