Check out the Evaluating Websites Research Guide.  As a general rule, never trust a website that does not clearly state who the author(s) are.  Remember that organizations, universities and businesses are often the authors of reliable websites. If, for example, you want medical information, go to the Mayo Clinic or the Center for Disease Control and Prevention (CDC) because they have a well earned reputation for medical expertise. If you have a question about a specific source, ask a librarian.