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 Imagine a World Without Justin Bieber, It's Easy If You Try Looking for Proof of Social-Media ROI? For Starters... By Simon Dumenco, Published on October 15, 2012 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. Register Now Already a member? Log in.