HEALTH MANAGER: A woman in Ji'nan, Shandong Province, takes a blood pressure test at a cloud computing terminal, which is designed to give users healthcare instructions based on big-data analysis (ZHU ZHENG)

This year, for the first time in history, people were able to watch the world's largest annual migration of people, the holiday rush before the Chinese Lunar New Year, also known as the Spring Festival, in real time.

Five days before the festival, which fell on January 31, Chinese search giant Baidu launched an online, real-time map of the migration at Qianxi.baidu.com, which was updated hourly based on the average traffic of the previous eight hours. The digital map illustrated which paths were the most common and provided detailed information such as where people leaving the big cities were heading to, and which cities and provinces received the largest number of new arrivals, among other interesting insights.

According to Baidu's press release, the information is built on data from the more than 3.5 billion daily positioning requests sent to the company's location-based service (LBS) open platform through products that use its positioning technology and services, including Baidu Map mobile app.

Although the migration map is no longer being updated after the end of the Spring Festival holiday, the event triggered enormous interest in "big data," which had never been so vividly visualized in the media.

Big data is a relatively recent term that has been coined to describe the easy-to-follow trail of digital footprints Internet users inevitably leave behind revealing who they are, what they buy, where they go, and much more. In this new era of Internet use, an astronomical amount of data is collected, shared and processed by website companies.

"Every one of us contributes to this massive data pool. It is estimated that by 2020 an ordinary Chinese family will produce data equivalent to half of the information stocked in the National Library of China," said Tang Xiongyan, chief engineer of the Research Institute of China Unicom, one of the country's three largest telecom service providers. The National Library of China in Beijing is the largest library in Asia and one of the largest in the world, having accumulated a collection of over 31.19 million volumes of books by 2012.

The most visible utilization of big data is the tailored pop-up advertisements based on information about Internet users' shopping preferences, according to Zheng Ning, an associate law professor at the Communication University of China. She said that enormous potential in using this information to attract customers exists for insurance companies, healthcare providers and telecom service providers among others.

Merits and risks

Before Baidu launched its online migration map, the company tried the technology out on a smaller scale by tracing pedestrians around subway stations, shopping malls as well as drivers on the roads in Beijing.

According to Gu Weihao, Chief Technology Supervisor of Baidu's LBS department, the data collected through these three channels could be used by the government to improve the efficiency of utilities around subway stations and better allocate public resources within a business circle. It can also help drivers to find the best route to a destination by avoiding traffic congestion, he added.

Yet these opportunities bring with them increasing challenges related to security and privacy.