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 U.S. User Growth Slowing, Twitter Faces Tougher Slog In International Ad Markets 77% of Users Are International, but Only 25% of Revenue Comes from Abroad By Cotton Delo, Published on October 04, 2013 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. Become a Member Already a member? Log in.