The Citizen Lab has documented a pattern of Internet filtering in Pakistan that is inconsistent and intermittent with with filtering primarily targeted at content deemed to be a threat to national security and at religious content considered blasphemous. In recent years, Twitter, Facebook, and certain pages on Flickr and Wikipedia have been periodically blocked in the country due to what was considered blasphemous content circulating on those sites. Bytes for All (B4A), has been campaigning for the online rights of Pakistani citizens and an active participant in the debate on the use of information communications technologies for sustainable development and strengthening human rights movements in the country.