A form filled in by a visitor when accessing a Web site. Often these forms ask for basic information such as your name, email address, and phone number. They are sometimes used for legitimate purposes: for example, for the notification of Web site updates. However, guest books are often used by mailing list compilers who sell the lists to users who carry out spamming. Web designers use guest books with discretion: often, asking a visitor to a Web site to fill in a guest book results in their leaving the site.