Plaintiffs accusing Google of scanning their email without permission have significant challenges in their class action lawsuit, a federal judge said on Thursday. Nine plaintiffs have brought charges against Google claiming that the company violated federal anti-wiretapping laws by scanning their emails to serve ads. Some of the plaintiffs were not Gmail users and U.S. District Judge Lucy Koh has said that plaintiff attorneys faced a "huge hurdle" to demonstrate that the non-Gmail users were entitled to class action status.