Cookies are files stored by the web browsers during visits to web pages.
The information is then sent back to the server when requests are made. This enables a web server access to information identifying the web browsers.
There are two main kinds of cookies: session cookies and persistent cookies. Session cookies are deleted from your computer when you close your browser. Persistent cookies remain stored on your computer until deleted or until they expire.
Most browsers allow you to refuse to accept cookies usually within the Options or Privacy menus of the specific browser. However, blocking cookies will have a negative impact upon the usability of this and other websites.