In 2004, thirty-one privacy and civil liberties organizations wrote a letter calling upon Google to suspend its Gmail service until the privacy issues were adequately addressed. The letter also called upon Google to clarify its written information policies regarding data retention and data sharing among its business units. The organizations also voiced their concerns about Google's plan to scan the text of all incoming messages for the purposes of ad placement, noting that the scanning of confidential email for inserting third-party ad content violates the implicit trust of an email service provider.