[Guardian] Internet censorship: how does each country compare?
Censorship of internet content can take many forms and ranges from governments blocking the dissemination of political opinion to blacklisting pornographic and pirate websites. [...]
According to the ONI data, Iran was the worst ranked, with "pervasive" filtering in the political, social and internet tools categories and "substantial" for conflict/security filtering. Tested in 2011, Iran's filtering was rated as being "highly" consistent and had "medium" transparency. [...]
After Iran was China, which had "pervasive" political and conflict/security filtering, along with "substantial" internet tools and social filtering. In addition to highly consistent filtering, China also had a lower transparency score than Iran. [...]
However, Deibert feels governments are moving away from widespread blacklists of websites to filter and towards what the ONI calls "next-generation filtering," which includes targeted surveillance and "just in time" filtering, or temporarily filtering content only when it's valuable – for instance, during an election. [...]