The Socialist Republic of Vietnam regulates access to the Internet by its citizens extensively, through both technical and legal means. This study by the OpenNet Initiative (ONI) finds that the Vietnamese state attempts to block citizens from accessing political and religious material deemed to be subversive along various axes. The technical sophistication, breadth, and effectiveness of Vietnam's filtering are increasing with time, and are augmented by an ever-expanding set of legal regulations and prohibitions that govern on-line activity.
http://www.opennet.net/studies/vietnam/ONI_Vietnam_Country_Study.pdf
