Matthew Devost, president of Total Intelligence Solutions, a risk management firm based in Arlington, Va., said for federal law enforcement agencies, the intelligence benefit of leaving such sites operating is often greater than shutting them down.

“In some cases, it may be that companies and or the government is aware of these sites, but what they post there gives us intelligence that we’d rather have,” Devost said. “Sometimes there’s a general concern that if you shut down these sites, while they might move to somewhere else online where they start making it password protected or otherwise harder to get access to the content.” (Washington Post)