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 Holy Grail of Targeting Is Fuel for Privacy Battle Melding of Online and Offline Info Is Delicate Dance for Marketers, Could Raise Red Flag to Regulators By Michael Learmonth, Published on March 22, 2010 12 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. Register Now Already a member? Log in.