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 Sprint Partners With Telefónica to Form Mobile Ad Network Mobile Carriers Under Pressure to Ad Revenue Streams By John McDermott, Published on February 20, 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.