The 21st century is the age of IT development. There are many SNSs such as blogs, online agoras like Facebook, and Twitter where people upload their news and show their lives to acquaintances or even to strangers. Because of those media, users are always exposed to and chased by the public. They cannot do what they want to do because all of their friends know where they are and when they are free.
People also feel that someone may monitor them all the time. This ?omeone?is sometimes called Big Brother. Big Data  is one of the reasons people being monitored, which many people confuse with Big Brother. Big data is database management technology, which collects a lot of data and selects specific information through vast analysis. The size of it already reaches petabytes and increases continuously. One of the defining criterion of Big Data is 3V, big volume, fast velocity, and high variety of information. Big Data technology categorizes collected data to affirmation, negation, or neutrality, according to link strength in social network. It also estimates users’ fame and influence and finally makes a group of similar individuals. The development of Big Data offers customized information to individuals and manages the information. It predicts trends of modern society. Big Data is used in all fields, such as politics, economy, culture, and science technology.
However, most people think from Big Data has more negative points than positive ones. The biggest issue is invasion of privacy as mentioned above. People cannot hide themselves or ignore others because of the openness of some Big Data. People also doubt each other and the accuracy of the news.
As Big Data develops, security is very important. If information is compromisal, it can result in enormous damage, because it is not only about name, phone number, or online ID but also the records of credit cards and hospitals, living area, and other personal information. Furthermore, the more it is developed, the easier the hackers can find what they want.
Companies also use Big Data to advertise more efficiently. They analyze users’ consumption tendency to propose their products faster and more effectively than others. Big Data knows what someone bought and where she went yesterday. This is very similar to Big Brother, just different in that continuous observation and analyzing are used not for political suppression but for commercial benefits. In fact, Big Data guarantees anonymity fundamentally in analyzing patterns of customers. Big Brother refers to the government using individual information to control individuals. Therefore, if Big Brother has Big Data, it could be really detrimental to democracy. Big Data could generate Big Brother. Big Data must be closely observed to protect people? privacy and prevent it  from becoming more than a marketing tool.