A/HRC/33/29 surveillance, they may actually facilitate it.” 69 The same is true in relation to controlling content online. While the Internet has unleashed huge potential for the free flow of information, there is also an expanded possibility of overreach by States in which the Internet is extensively controlled. 52. A key component of many policies and measures aimed at preventing and countering violent extremism is focused on effectively responding to violent extremism online. The level of intrusiveness of measures and their impact on human rights depends on the definition of notions such as “extremism”, “violent extremism” and “radicalization” and the perceived role played by extremist ideas, including exposure to such ideas, in processes leading individuals to turn to violent extremism or terrorism. 53. Restrictions on access to information and communications technology range from complete network shutdowns or disruptions, to blocking access to certain platforms, to imposing restrictions on individuals connecting to, or using, certain technologies. The blocking or removal of specific content has been used as a measure to counter violent extremism. States invoke various reasons for the necessity of employing such measures, including the need to prevent radicalization, violent extremism and the recruitment of foreign fighters; countering incitement to acts of terrorism; and stopping the dissemination of terrorist material. 54. The above-mentioned measures, however, are at odds with the individualized assessment required under human rights law. States have to provide evidence-based justification of the necessity and proportionality of such interference with freedom of expression. They must demonstrate how the perceived benefits of these measures outweigh the importance of the Internet as a tool to maximize the number and diversity of voices in the discussion of numerous issues. Any lack of transparency with regard to blocking or content removal measures renders it difficult to assess whether such restrictions were really necessary for the purported aim. Consequently, there is a need for much greater transparency by States to clarify what content they are filtering, blocking or removing and on what basis. 55. States may also use information and communications technology companies to control and regulate access to content in the digital space. When doing so, States resort to formal legal processes, including court orders and intermediary liability systems, that force companies to actively monitor content, or to more diffuse forms of pressure to cooperate. Host providers and social media platforms face increasing pressure to actively monitor and police content generated or disseminated by users, a trend exacerbated by the use of information and communications technology by violent extremists and terrorist groups. 56. Another frequently employed means in the fight against violent extremism is the monitoring of online content: surveillance, interception, collection and retention of data. Some States have claimed that mass surveillance is “necessary” to detect terrorist plots and identify terrorists, violent extremists, their recruiters and other supporters.70 The gathering, storage and use of data can have an impact on a number of human rights, including the rights to privacy, freedom of peaceful assembly and association, and freedom of movement.71 The Special Rapporteur on the promotion and protection of the right to freedom of opinion and expression highlighted that online surveillance may also undermine the right to form an opinion, as the fear of unwilling disclosure of online activity, such as 69 70 71 16 See A/HRC/27/37, para. 2. A/69/397. See A/HRC/13/37, paras. 33-38.