Up to now, referrers for clicks on ads for the term "flowers", for example, would be one of the following:
http://www.google.com/search?...&q=flowers&...
http://www.google.com/aclk?...&q=flowers&...
We’re adding a third possible referrer:
http://www.googleadservices.com/pagead/aclk?...&q=flowers&...&ohost=www.google.com&...
This new referrer is on a different domain named ‘www.googleadservices.com’, and has a new path of ‘/pagead/aclk’. The query is still there as the GET parameter ‘q’ and the originating host for the click is there as the GET parameter ‘ohost’. For example, if the click came from google.ca, the new referrer format would be http://www.googleadservices.com/pagead/aclk?...&q=flowers&...&ohost=www.google.ca&...
We’re making this change because we’re trying to improve the experience of clicking on an ad for our users