This is a script that reminds your surfers to bookmark your site whenever he/she leaves the page.

To avoid over-irritating your surfers, the message appears only the first time the surfer enters and leaves the page; if he/she goes to CNN for a while, then returns and leaves again, the message is not displayed. 

This script uses cookies to keep track of the number of times the user has entered/left the page, thus, the browser the surfer is using must be cookie enabled to see any message at all.