The US Supreme Court declined to hear an appeal from Google on a class-action lawsuit brought against it by advertisers.
The court's decision Monday will leave in place a ruling from last year in a San Francisco federal court. That means the lawsuit can move forward as a class action representing thousands of advertisers who previously used Google's AdWords program from 2004 to 2008.
The suit, filed in 2008, claims advertisers were misled about where their ads were placed online. AdWords is primarily used to put ads next to relevant Google searches, but the plaintiffs said Google also put their ads on third-party sites without properly disclosing that information. In some cases, the plaintiffs claimed, their ads appeared on error pages and other undesirable pages.
A Google representative said the company doesn't comment on pending litigation.
Google is by far the leader in worldwide digital ad revenue, bringing in about 30 percent of all digital ad dollars last year, according to researcher eMarketer.