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 Facebook Ads Not Working? Try Facebook Credits The Virtual Currency Has High Value for Millions of Social Gamers By Michael Amar, Published on June 13, 2012 8 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.