AdWords began showing only one ad per display URL, limiting affiliates sharing a merchant's domain

Google changed its affiliate policy so that only one ad from an affiliate or parent company sharing the same display URL would show for a given query, with Ad Rank deciding which one appeared. Affiliates were no longer required to label themselves as such, but ads relying on redirects or frames became subject to disapproval.

The change was announced to advertisers in early January 2005 with an effective date of January 12, and WebmasterWorld members reported seeing the duplicate-URL filter in live results by January 13-14. No official Google post for this change has been located, so it is recorded from contemporary forum coverage.