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 AmEx Opens Up Data Treasure Trove Will Offer Transaction Information on its 90M Members to Businesses By Beth Snyder Bulik, Published on November 30, 2009 2 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.