A cookie is a small file which asks permission to be placed on your computer's hard drive. Once you agree, the file is added and the cookie helps analyse web traffic or lets you know when you visit a particular site. Cookies allow web applications to respond to you as an individual. The web application can tailor its operations to your needs, likes and dislikes by gathering and remembering information about your preferences.
There are two types of cookies:
Session (Transient) cookies: These cookies are erased when you close your browser, and do not collect information from your computer. They typically store information in the form of a session identification that does not personally identify the user.
Persistent (Permanent or Stored) cookies: These cookies are stored on your hard drive until they expire (i.e. the are based on a set expiration date) or until you delete them. These cookies are used to collect identifying information about the user, such as Web surfing behaviour or user preferences for a specific site.