Internet censorship is when someone tries to control what other people can access on the Internet
Some governments use censorship to restrict access to certain information
One of the strictest countries for censorship is China
China restrict access to websites which are critical of government - they also censor many major foreign websites including Facebook, YouTube and Twitter
In Cuba , citizens can only access the Internet from government-controlled access points
Many governments use some form of censorship - Many countries (including the UK) restrict access to pornography, gambling and other inappropriate websites to protect children
Computer surveillance is when someone monitors what other people are accessing on the Internet
Government intelligence agencies may use packet sniffers and other software to monitor internet traffic , looking for key words or phrases that might alert them to illegal activities , terrorism etc.
In some countries, Internet Service Providers (ISPs) keep records of all websites visited by all its customers for a certain amount of time
Censorship and surveillance are controversial topics
Some people support censorship and surveillance , in order to protect children or to stop terrorism
Several non-profit organisations are against censorship and surveillance, and campaign against what they call cyber censorship and mass surveillance