The detailed activity browser in the reports area of the Advertising section has been updated to include the URL of the document that displayed the ad. This information is reported for both Clicks and Impressions.
The changes were made with the intention of assisting advertisers in spotting suspicious activity – it is now possibly to see if a visitor to the site has clicked the same ad on the same page more then once, for example. A secondary advantage is that advertisers will be able to see where their clicks are originating.
Visitor privacy is maintained by stripping all values from the page URL, so although an advertiser can see that a visitor has visited (eg) the forums, they cannot tell exactly which threads that visitor has looked at.
Minor Update:
IP Hostnames have been added in order to help track scammers, spammers and bots.
You can read about the Advertising service, here.

