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 How Brands 'Celebrated' Martin Luther King Day on Twitter Which -- if Any -- Got it Right? By Nat Ives, Published on January 20, 2014 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.