You’ve read all of your free items this month. To register, get added benefits and unlimited access to articles, Become a Member. Already a Member? Sign in. Advertising Age Article Abstract Marketers, Agencies, Google Spar Over Brands' Precious Data Clients Unsure Whether to Trust Agencies With Customer Data By Tim Peterson, Published on March 18, 2014 0 Want more Access, Content & Connections? Upgrade to Membership. We are glad you are enjoying Advertising Age. To get uninterrupted access and additional benefits, become a member today. Become a Member Already a member? Log in.