PENTAGON CITY: We’ve all heard about social media and its influence on international affairs and national security. The Arab Spring blossomed when a Tunisian man’s self-immolation was shared online and sparked uprisings that have yet to subside.

But you don’t really think of social media as a useful tool for detecting weapons and their use. After all, we’ve got spy satellites (DSP and SBIRS) that watch for missile launches, and radar satellites that look for a wide array of weapons, and aircraft like AWACS and JSTARS that watch the skies and the ground for us.

But the head of the Defense Intelligence Agency told an audience of several hundred intelligence contractors at the annual Intelligence and National Security Alliance’s (INSA) dinner last night that the first time we learned of Yemen’s Houthi rebels’ June launch of a SCUD missile against Saudi Arabia, the intelligence did not come from the oft-praised Space-Based Infrared System (SBIRS) or the aging but reliable DSP satellites built to watch for and detect missile launches around the world.

DIA Director Lt. Gen. Vincent Stewart speaks at INSA dinner

“First warning of that event? Hashtag SCUDlaunch,” he said. While the tweet didn’t exactly tell us where the missile was launched from, Marine Lt. Gen. Vincent Stewart made clear it probably helped us retarget our satellites, drones and other assets to find it: “That’s how we started the search for that act.”

The general made it clear there are other unwelcome things being found by DIA. While he provided no details, Stewart said last night that a sweep of the agency’s networks by counterintelligence experts “surfaced some things that concerned us.”

Other things concern him as well, including the slow turnover at his agency, which replaces only 5 percent of its workers each year. He complained of ossified analysts — especially those dealing with Cuba — who found it difficult to adapt to our fast-changing world. He said he would press for analysts to get certifications — which even fork lift operators receive, he noted — and encouraged folks who weren’t comfortable at his agency to heard over to CIA or other intelligence agencies. He poked at the CIA several times during the evening, eliciting knowing laughter each time from an audience all too familiar with the internecine budget and personnel wars the three-letter agencies regularly wage.

For those who wondered what changes might be made to DIA’s acquisition efforts, Stewart was wonderfully blunt. First, he joined Arnold Punaro in calling for the entire acquisition system to be scrapped and rebuilt. Then he very pointedly told the audience to reign in their lawyers and, “Quit protesting everything.” Not going to happen, but never mind. It probably made some people feel better.