Hvad er cookie_life_span

En hurtig søgning på google gav følgende:
http://www.bjawnie.com/products/counterhit/
Under punkt 5 Configuration står der:
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The variable "cookie_life_span" has no importance if you have turned off the above "unique hits".
"cookie_life_span" defines how many days there has to pass before a user who once has visited your site, will "add a hit" to the site if he visits your site again.
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Ved ikke om det kan bruges, ellers må du vente på der kommer en med mere viden om det.