By contrast, a 2002 study found that only two countries censored the Web, says Palfrey, who is also an investigator at OpenNet.

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According to a 2007 report by the OpenNet Initiative, which surveyed more than 40 countries, almost two-thirds of the states involved were filtering content to some degree.

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Now, that curtain has risen slightly: Users can again send e-mail and access the Web, according to Ron Deibert, director at the University of Toronto's Citizen Lab and an investigator at the OpenNet Initiative.

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According to a 2007 study by the OpenNet Initiative--a collaborative effort by researchers at Harvard, Oxford, Cambridge and the University of Toronto to investigate Internet censoring--as many as 26 countries engage in some type of Web censoring.

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"The IGF Secretariat approved the request by the OpenNet Initiative (ONI) for a room on the first day of the Forum to promote the book Access Controlled and a room was allocated for that purpose, " it said in a statement.

BBC: UN slated for stifling net debate