In 1948, George Orwell wrote an often referenced book called Nineteen Eighty-Four in which people were under constant surveillance by the government, even in their homes, through digital equipment. The government was represented by a fictional character called Big Brother and the people were constantly reminded that 'Big Brother is watching you'.
Big Brother was not just observing people, Big Brother also managed people by interfering in their lives to produce a perfectly obedient citizen. When you hear Google referred to as 'Big Brother', they are referring to this book.