Last week Google announced a subtle change to their Display URL Policy. They are now requiring any advertising that lands on pages that live on hosted domains (large domains that allow different users to have pages on them) must represent the sub domain in the display URL.
Google has always placed an emphasis on transparent advertising practices, their search results are only as relevant as the ads on the page. This keeps the quality of their search results high, leading to users to find value and return to search again and again. Deception is not tolerated and heavily penalized in any capacity. For instance, an ad that tries to fool the user on what website they are clicking to is not able to run on Google’s network.
By having to include sub domains in the display URL Google is making another move towards transparency in their advertising and allowing users to be well aware of where they are clicking. This is also consistent with Google’s recent step up of tactics to combat advanced affiliate networking which the search engines find as barriers between users and content. By having to display the sub domains it will be harder to hide landing pages on large domains.
Utilizing sub domains on hosted sites may have some advantages to advertisers, but Display URLs are set to a limit of 35 characters. If you remove the top level domain (“.com”, “.net”, etc.) you now have 31 characters left to list the sub domain, domain, and any other text to bring relevance to the page. Every character in an ad counts and now having to list sub domains will limit opportunities to capture search traffic.
Google has valid reasons for updating their policy. The move strengthens the value of the search results and combats those who try to interrupt the path searchers follow to the content they are looking for. Any drawbacks to optimizing the display URL are greatly outweighed by the accuracy and transparency it provides.
A greater impact will be felt if the policy is expanded to all landing pages that include sub domains, going beyond hosted domains to also regulate private domains.
Google’s Announcement Here: http://adwords.blogspot.com/2010/01/policy-adjustment-for-display-urls.html