“We’re still trying to figure out how you use things like Twitter as a source,” she said. “How do you establish trends and how do you then capture that in an intelligence product?”

Wagner said the department is establishing guidelines on gleaning information from sites such as Twitter and Facebook for law enforcement purposes. Wagner says those protocols are being developed under strict laws meant to prevent spying on U.S. citizens and protect privacy, including rules dictating the length of time the information can be stored and differences between domestic and international surveillance.

Wagner said the Homeland Security department, established after the 9/11 attacks, is not actively monitoring any social networks. But when the department receives information about a potential threat, contractors are then asked to look for certain references within “open source” information, which is available to anyone on the Internet.