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 Slowly But Surely, Line Extensions Will Take Your Brand Off Course Beer Category Shows Cannibalization of Core Brands By Al Ries, Published on September 07, 2009 18 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.