Cookies (also web cookie, http cookie, browser cookie) are used to send status organisations to the web browser, which then sends them back to the original page from which the cookie originated.

Status information is used for user authentication, user session recognition, user settings, shopping cart contents, and similar tasks. Cookies cannot be programmed, cannot contain viruses, and cannot install malware on a user's computer, but they can be misused by spyware to track browser behavior. Cookie data can also be misused by hackers.

Thus, cookies can allow browsers to remember a user's session, for example at eshop, where a cookie remembers items that the user has placed in the cart but does not yet want to order. The user is thus free to move around the e-shop and the cookie keeps the selected items in the shopping cart at all times.

Cookies are also very often used to personalise content – for example, they can remember the username and password that have been filled in, so that the user does not have to re-enter these details each time they visit the site. Google uses cookies, for example, to remember how many results to display on a page for a user, whether they are logged in or not.