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 New Twitter Rules Clamp Down on Ad Networks Move Will Affect Startups Such as Ad.ly and Sponsored Tweets, but Users May Still Sell Their Own Tweets By Michael Learmonth, Published on May 24, 2010 5 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.