Private firms and open sources are giving spies a run for their money

As railways expanded across America in the 19th century, there was little law enforcement. Rail barons needed to keep track of threats. The Pinkerton detective agency frequently filled the gap, recruiting informants and passing dossiers to sheriffs. “That was the booming technology of that era,” says Andrew Borene, an American former intelligence officer. Today it is the internet. Mr Borene is executive director of Flashpoint, a “threat-intelligence” company which monitors terrorist groups and hostile intelligence services online, selling the information to governments and businesses. A few decades ago that work would have been the preserve of spy agencies.