3. Filtering and Blocking
a. Mandatory blocking of entire websites, IP addresses, ports, network protocols or types of uses (such as social networking) is an extreme measure – analogous to banning a newspaper or broadcaster – which can only be justified in accordance with international standards, for example where necessary to protect children against sexual abuse.
b. Content filtering systems which are imposed by a government or commercial service provider and which are not end-user controlled are a form of prior censorship and are not justifiable as a restriction on freedom of expression.
c. Products designed to facilitate end-user filtering should be required to be accompanied by clear information to end-users about how they work and their potential pitfalls in terms of over-inclusive filtering.