The cookie is named after the fortune cookie - the confection with a message inside. It is a small block of data that will, if accepted, be saved on your hard disk. Then, when you next visit the Web site that sent it, your browser will send the cookie back to the server. They are often used for various kinds of personalisation - the date you last visited a site or the particular Web pages that interested you. From such data you may, for example, be offered personalized information when you next visit the site. Many legitimate and useful sites (such as online banking and online ordering) now require cookies (and also "active scripting" and the like) to be enabled, so that it can become impractical to keep making exceptions to otherwise secure browser settings.

For more information on cookies, see http://www.cookiecentral.com

Browser parasites have now become common. These are pieces of software that, when you visit a Website, may exploit security weaknesses in your browser or an inattentive mouse click and install themselves on your machine without your being aware of them. They then do things such as displaying pop-up advertisements. A free check for parasites can be carried out by visiting: http://www.doxdesk.com/parasite/