A trawl of Chinese crowdsourcing websites—where people can earn a few pennies for small jobs such as labeling images—has uncovered a multimillion-dollar industry that pays hundreds of thousands of people to distort interactions in social networks and to post spam.
The report’s authors, at the University of California, Santa Barbara, also found evidence that crowdsourcing sites in the U.S. are similarly dominated by ethically questionable jobs. They conclude that the rapid growth of this way of making money will make paid shills a serious security problem for websites and those who use them around the world. A paper describing their results is available on the Arxiv pre-print server.
Ben Zhao, an associate professor of computer science at UCSB (and a TR35 winner in 2006), started looking into the largely uncharted crowdsourcing industry in China after working closely with RenRen, a social network that is sometimes called the “Facebook of China,” to track malicious activity on the site. Zhao was intrigued to see a lot of relatively sophisticated attempts to send spam and promote brands by users that appeared to be working with specific agendas.
When he and colleagues investigated the source of that activity, the team was surprised by what it found, says Zhao: “Evil crowdsourcing on a very large scale.” Influencing public opinion with fake “grassroots” activity is known as astroturfing, leading Zhao to coin the term “crowdturfing,” since it is done via large crowdsourcing sites.
The researchers discovered that a large amount of the suspect activity in China originated from two crowdsourcing sites: Zhubajie, the largest in China, and Sandaha. There, people are openly offered the equivalent of tens of cents to do things like create accounts on particular sites, post biased answers about specific products on Q&A sites, and create and spread positive messages about products on social networks.
“The websites are very public, and you can see who offered past jobs and what they paid,” says Zhao. His team used software to show that Zhubajie and Sandaha are, respectively, 88 and 92 percent crowdturfing. They also found that Zhubajie currently processes over a million dollars every month for crowdturfing tasks; the figure for the younger Sandaha is tens of thousands of dollars. “This industry is millions of dollars per year already and [shows] roughly exponential growth,” says Zhao. “I think we’re still in the early stages of this phenomenon.”