【明報專訊】AT the Christchurch Call Summit held in Paris, France last week, 17 countries and the EU as well as technology giants joined an action plan initiated by New Zealand to "eliminate terrorism and violent extremism online". The framework agreement of the summit includes accelerating research into and development of technical solutions to prevent the upload of violent extremist content online and to detect and immediately remove it; providing greater transparency in the setting of community standards or terms of service; and reviewing the operation of algorithms and other processes that may drive users towards and/or amplify terrorist and violent extremist content. Meanwhile, the Board of Supervisors of San Francisco, the US, approved an ordinance last week banning the use of face recognition technology by the municipal government in a bid to prevent the surveillance of citizens and privacy infringement. The two events underline the importance of finding the appropriate boundaries of and striking a balance between freedom of speech, privacy, combating crimes and fighting terrorism in the current world of rapid technological advance.