Actually, the control of the Internet has been practised by Vietnam for a long time. With the police security they have a special branch to manage and monitor the activities on the Internet. They also installed a firewall that prevents the people from getting the news from outside. They also had a government decree signed by the Prime Minister himself forbidding the people to use the Internet for spreading ideas of democracy and freedom.
On May 12th, 2015. See this statement in context.