The Federal Bureau of Investigation is giving an entirely new meaning to "following" a securities fraud suspect. Instead of unmarked vehicles and dark sunglasses, think 140 characters or less. That's right, Twitter and Facebook.

According to a Reuters article this morning, the FBI has been using sites like Twitter and Facebook to monitor communications that could be construed as insider trading.

April Brooks is the special agent in charge of the criminal division in New York, and she says the FBI is on these social networks because crime fighting, like insider trading, is about human communication.

"We're a human organization," says Brooks. "We talk to people on the street -- whether it's a person on Wall Street, whether it's someone from a business, 99 percent of our information comes from the public or human sources."