By 2009, the collection was extensive. One document says that while GCHQ was testing its ability to spy on Second Life in real time, British intelligence officers vacuumed up three days' worth of Second Life chat, instant message and financial transaction data, totaling 176,677 lines of data, which included the content of the communications.
For their part, players have openly worried that the NSA might be watching them.
In one World of Warcraft discussion thread, begun just days after the first Snowden revelations appeared in the news media in June, a human death knight with the user name "Crrassus" asked whether the NSA might be reading game chat logs.
"If they ever read these forums," wrote a goblin priest with the user name "Diaya," "they would realize they were wasting" their time.
Even before the American government began spying in virtual worlds, the Pentagon had identified the potential intelligence value of video games. The Pentagon's Special Operations Command in 2006 and 2007 worked with several foreign companies -- including an obscure digital media business based in Prague -- to build games that could be downloaded to mobile phones., according to people involved in the effort. They said the games, which were not identified as creations of the Pentagon, were then used as vehicles for intelligence agencies to collect information about the users.
Eager to cash in on the government's growing interest in virtual worlds, several large private contractors have spent years pitching their services to American intelligence agencies. In one 66-page document from 2007, part of the cache released by Mr. Snowden, the contracting giant SAIC promoted its ability to support "intelligence collection in the game space," and warned that online games could be used by militant groups to recruit followers and could provide "terrorist organizations with a powerful platform to reach core target audiences."
It is unclear whether SAIC received a contract based on this proposal, but one former SAIC employee said that the company at one point had a lucrative contract with the CIA for work that included monitoring the Internet for militant activity. An SAIC spokeswoman declined to comment.
In spring 2009, academics and defense contractors gathered at the Marriott at Washington Dulles International Airport to present proposals for a government study about how players' behavior in a game like World of Warcraft might be linked to their real-world identities. "We were told it was highly likely that persons of interest were using virtual spaces to communicate or coordinate," said Dmitri Williams, a professor at the University of Southern California who received grant money as part of the program.
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