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 Ad Exchanges See a Premium-Level Future Ad Networks Try to Climb From Bargain Basement to the Penthouse By Daisy Whitney, Published on April 14, 2008 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.