Each time a visitor clicks on an ad on your web site, our system will count it as a raw click. A unique click is counted only once within a 24 hour-period. After 24 hours, the click on this ad from this visitor is counted again as a new unique click. A cookie is used to distinguish between unique and raw clicks.
Raw or Unique Impression "One visitor can view many ads. A raw impression is counted each time the ad is displayed to a visitor...." 65% relevant in ReportingOverview