Web Server
Figure 11: System Overview
There are several steps involved in the delivery (serving) of a banner. The first step is the actual banner request. This is a complicated process that queries our database tables to choose a banner to send back to the visitor. A list of possible banners is generated based on the site that the person is visiting. This list is narrowed down as banners with targeting schemes and frequency caps are eliminated if they don't meet the visitor's browser and profile specifications.
After the resulting list is determined, one banner is randomly chosen from the resulting list, using a scaled value calculated from the amount of loaded impressions remaining and the number of banners in the campaign. The web server redirects the visitor's browser to the URL of this banner.
The final step of the banner-serving process is done after the web request has finished. The web server logs which banner was served and on which site it appeared. If the banner is later clicked-on, a click-thru is also logged. This data is used to generate AdRunner's campaign, banner, and site history reports.
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