There may be several reasons why MedlinePlus does not point to a familiar or popular Web site.

• MedlinePlus is not a list of every Web page on health, but is a selected list of authoritative resources.
  
  
• Selection guidelines are used to evaluate every Web site that MedlinePlus points to.
  
  
• Multiple Web sites which contain the same information are not pointed to, even if different organizations, associations, companies or entities are responsible for their content.
  
  
• MedlinePlus tries to ensure that the information it links to is authoritative, accurate, up to date, educational and available at no charge.