Yahoo Search Marketing has informed advertisers that it has altered its trademark policy and will no longer allow competitor bids for keywords containing trademarks, starting March 1, according to a post by Jeremy Palmer on ReveNews. According to Yahoo's email to its advertisers, the move is intended "to more easily deliver quality user experiences when users search on terms that are trademarks."

Under the previous policy, Palmer writes, ads would be approved "as long as your competitive comparison was (somewhat) objective and informative…. If your competitive comparison had false or misleading information, they would not be approved. Plus, there was always an option for the trademark holder to dispute the validity of the ad."

According to Yahoo, "advertiser listings that qualify under the reseller or non-competitor information guidelines may be allowed, subject to Yahoo's discretion to accept or reject listings."