The Central Intelligence Agency (CIA) has established a compound in Virginia that focuses on one very important aspect of international espionage: social network spying.

According to the Associated Press, which was provided some insight into the CIA's operations, the Open Source Center, a team also known as the "vengeful librarians," analyzes up to 5 million tweets a day to gauge public opinion around the world. The group also examines messages shared via Facebook and comments made in Internet chat rooms, in addition to listening in on more traditional forms of information dissemination, such as TV news channels and local radio stations.

But before U.S.-based privacy advocates get too concerned about the CIA's practices, it's worth noting that the entirety of its actions, the center's director, Doug Naquin, told the AP, centers on the examination of social activity in other countries.

The U.S. government is barred by law from spying on tweets, Facebook messages, or e-mails sent by U.S. citizens without a warrant.

According to the AP, the Open Source Center was first established after the 9/11 attacks to combat international terrorism. But now, the group told the AP, its focus goes far beyond a focus on terrorism, and examines public opinion on a host of matters around the world.

For example, the group told the AP, it provided information to "the highest levels at the White House" on the Middle East's reaction to this year's killing of Osama bin Laden. The group told the AP that it found that the majority of Urdu tweets and Chinese tweets were negative, seeming to indicate that the Pakistani people and Chinese were not pleased with the news. After President Obama announced bin Laden's death, reactions on social networks were negative in several countries in the Middle East.

The stakes appear to be high for the vengeful librarians. According to the AP, their analyses of tweets, messages, and other citizen reactions around the world find their way into the President's daily briefings, and thus, play a role in his decision-making.

However, even though the intelligence community has continued to say that it doesn't engage in any spying of U.S. citizen communications, not everyone is so convinced.

In 2009, for example, Greg Nojeim, an attorney for the Center for Democracy and Technology sat down with CNET to discuss the possibility of the U.S. government spying on its citizens' online communications. As far as he was concerned at the time, the U.S. could spy on its citizens, although there was no way to prove that it does, in fact, do so.

"Who wants to live in a world where the government can listen in on every communication without any evidence of crime?" Nojeim said. "The consequences of that are that people won't communicate freely and the country would be very different as a result. Imagine how your conversation with a close personal friend would change if you knew someone else was listening. That's what is at stake. That's what needs to be protected."

Julian Assange, the founder of WikiLeaks, which has exposed U.S. diplomatic cables, videos from the wars, and more, is also concerned that some of the most prominent online companies--Facebook and Google, among others--are tools for the government to be used for access to any kind of information they want.

"Facebook in particular is the most appalling spying machine that has ever been invented," Assange said in an interview with Russian news site RT earlier this year. "Here we have the world's most comprehensive database about people, their relationships, their names, their addresses, their locations and the communications with each other, their relatives, all sitting within the United States, all accessible to U.S. intelligence."

Assange went on to say that the companies "have built-in interfaces for U.S. intelligence."

"It's not a matter of serving a subpoena," Assange told RT. "They have an interface that they have developed for U.S. intelligence to use."

It's worth noting, however, that neither those companies Assange mentioned nor the U.S. intelligence community have ever confirmed that they are working in cahoots to spy on people.