The phrase refers to the government’s surveillance of the people with listening devices and cameras, in a totalitarian society, where Big Brother is the head of the totalitarian regime. Everyone in this society is under surveillance by the authorities, which reminds people of an endless catchphrase “Big Brother is watching You,” showing a dictator’s mindset of a Big Brother. It means nobody is over the rule, it might show a dictatorship move towards the citizen but it's still being followed the rule by the regime.