On Friday, the Federal Bureau of Investigation, Department of Homeland Security and National Counterterrorism Center sent out a joint bulletin informing law enforcement and military personnel that, although there were no credible threats hovering over holiday weekend events, officials are “aware of recent information suggesting US military bases, locations, and events could be targeted in the near-term.”

Happy Memorial Day!

This information isn’t really news to anyone following national security and foreign policy news, but the reason for the concern is novel: the dramatic uptick in social media activity by groups like ISIS has led to new sources of “insider threats” and chatter about security and maintenance procedures at sites that officials now believe are being considered as potential targets.

Fox News has the exclusive:

Importantly, it speaks to the sheer volume of social media activity by pro-ISIS users, and the challenge that poses for analysts and investigators.

“The large number of social media postings by US-based ISIL supporters is challenging for investigators in differentiating those supporters focused only on promoting pro-ISIL rhetoric, which may be protected speech, vice [versus] detecting those prepared to engage in violence on the group’s behalf,” the bulletin said.

The bulletin warned the “reach and popularity” of social media platforms has made it easier for U.S.-based extremists to “identify and connect” with foreign terrorist organizations, which can “potentially direct” them. It said the FBI estimates there are “hundreds, possibly thousands” of people in the U.S. getting “recruitment overtures or directives to attack the United States,” and ISIS is using social media in “unprecedented ways” to send messages advocating attacks in the U.S.

The bulletin also encouraged those who maintain official military and government social media accounts to review their posts for anything that may attract the attention of violent extremists, and to “routinely exercise operational security in their interactions online.”

How impossible does that sound?

As a matter of policy, it makes sense for the FBI, et al., to encourage various agencies and installations to watch what they post online, if only in an effort to avoid extreme examples of rogue social media editors sharing provocative content meant to gain a reaction from those who sympathize with ISIS. And yet…how impossible is it to not capture the attention of a terrorist?

Pretty impossible.

The thing about terrorists is that their goal isn’t to take out the most strategically advantageous target; their goal is to create terror. If that means taking out an F16, a Chipotle, or a lost nun and puppy shelter, they’re going to do it. Even a hometown Memorial Day picnic could be considered a target if enough people attend, or will potentially pay attention after the bomb goes off.

In a lot of ways, technology has made the war on terror easier; even an extremist’s presence on social media can have an effect, if only to reenforce the idea that, yes, these people are real, and yes, these people will kill you if they think that your murder will send enough people into a state of complete and utter terror.

At the same time, when it comes to the internet, insanity reigns. A cursory scan of the general timeline on Tweetdeck uncovers no less than 50 tweets that could be classified as anything from “totally loony” to “completely bats**t insane.” Many ISIS sympathizers fall right in to the latter category, simply because the content of their message is so beyond the pale.

Now, imagine having to actually analyze thousands upon thousands of those tweets, knowing that to miss a pattern means missing the next great threat to our national security.

I don’t envy that job one bit.

You can read the full bulletin on the ISIS threat here. (At this time, only the first page is available—we’ll keep an eye on it.)