Censorship of internet content is growing across the world. A survey by the Open Net Initiative (ONI) across 41 countries found that 25 applied content filtering to block access to particular websites.
Web applications such as Google Maps and Skype as well as "subversive" websites featured on content blocking lists. Five years ago only a "couple" of states were exercising similar controls, according to John Palfrey of Harvard Law School, one of the researchers who took part in the study.
"There has also been an increase in the scale, scope, and sophistication of internet filtering," he told the BBC.
"Few states are open about informing their citizens about internet controls. There's no place you can get an answer as a citizen from your state about how they are filtering and what is being filtered," Palfrey said, adding that filtering almost invariable happens "in the shadows".
The extent of filtering varies between countries, with those in the Middle East among the most restrictive regimes. Burma, Iran, Pakistan, Saudi Arabia, Syria, Tunisia, the United Arab Emirates, and Yemen were among the states applying the heaviest use of the censor's "blue pencil". China, India, Singapore, South Korea, and Thailand all apply controls, albeit to a lesser extent.
Academics from the Universities of Toronto, Harvard Law School, Oxford, and Cambridge who make up the ONI reckon there are three main rationales for internet censorship: politics and power, state security, and the enforcement of social norms (such as a prohibition of pornography in Muslim states). Censorship nearly always falls across multiple categories. Controls, once applied, are often expanded to cover a broad range of content and used to increase government control of cyberspace.
Use of internet filtering leaves citizens with a restricted view of events unfolding around them, as well as restricting their knowledge of the outside world. The ONI study noted the growing use of techniques and tools used to circumvent filtering.
"It's hard to quantify how many people are doing this. As we go forward each year we want to see if some of these circumvention technologies become more like appliances and you just plug them in and they work," said Jonathan Zittrain, professor of internet governance and regulation at Oxford University. ®