Also called dynamic delivery . Hits are not the preferred unit of site-traffic measurement because the number of hits per page varies widely. Some commercial sites market on the basis of guaranteed impressions, eg the minimum times a banner will be seen as the user navigates through the site Metrics - a measurement of activity on the internet. A page often contains text plus images, ie comprises several data files, each of which constitute a 'hit' when retrieved by a browser Page views or page deliveries - the number of times a web page is requested. Unlike a hit, a request doesn't include client or server 'errors' Response rate - the percentage of impressions that result in clicks.
Sites often use identifiers such as cookies to differentiate between users .