A cookie is a piece of information in the form of a very small text file that is placed on an internet user’s hard drive. It is generated by a web page server, which is basically the computer that operates a web site. The information the cookie contains is set by the server and it can be used by that server whenever the user visits the site. A cookie can be thought of as an internet user’s identification card, which tells a web site when the user has returned.
Most Internet browsers allow users to control the acceptance of cookies via the browser’s settings. Visit allaboutcookies.org to find out how to configure these settings on a number of major browsers.
You can opt out of being tracked by Google Analytics across all websites by installing Google’s opt-out browser add-on.