Any web master trying to achieve top search engine placement has to be familiar with DirectHit technology. Click popularity and stickiness are two factors used in DirectHit's ranking formula. Click popularity measures the number of clicks every site in the search engine results page receives. If all of them click on the same page, DirectHit assumes that the page has more relevance and it will be scored higher next time.
Stickiness measures the amount of time that a user stays on a site.
This is measured by the time between clicks on the results page.