A small file placed on a user’s hard disk by a server, containing details about the user’s use of the website. It is returned to the server whenever the browser accesses the site. In general, cookies help the user and in some cases they are essential. For example, if the user is buying a number of items on-line, then a cookie is necessary for the server to keep track of items from different pages placed in a ‘shopping cart’. However, their use has raised privacy concerns and modern browsers allow users to block cookies either in total or from selected websites.