HARVARD, USA: Big Brother is watching the web more intently than ever before, according to a new survey of global internet censorship carried out by a collaborative partnership of four leading academic institutions. They report that 25 of 41 countries studied show evidence of content filtering.

Harvard Law School researcher John Palfrey, who works with colleagues at Oxford, Cambridge and Toronto Universities on the Open Net Initiative, says: "In five years we have gone from a couple of states doing state-mandated net filtering to 25."

He adds: "There has also been an increase in the scale, scope and sophistication of internet filtering."

Countries which carry out the broadest range of filtering include Burma, Iran, Pakistan, Saudi Arabia, Syria, Tunisia, the United Arab Emirates and Yemen, says the ONI.

These states engage in the practice for three main reasons: politics and power, security concerns and social norms.

But ONI is also looking at the ways in which web users get round state interference. Comments Jonathan Zittrain, at Oxford University: "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."

Palfrey adds: "What's regrettable about net filtering is that almost always this is happening in the shadows. 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."

Data sourced from BBC Online; additional content by WARC staff