America’s enemies include those who are “trolling social networks, blogs and forums,” a new Army document claims.

But don’t worry: leaving snarky comments won’t get you an early hours visit from the Green Berets. Trolling in this sense refers to foreign operatives reading through such sites for information that could compromise military security.

The warning comes in a 39-page document setting down the US Army’s social media policy, which effectively boils down to: go ahead, but don’t be stupid.

The document opens with a letter from the Army’s chief of public affairs, Stephen Lanza, who says military staff should “embrace social media.” The guide says “soldiers have always been the Army’s best and most effective messengers” and that social media allows every solider to “be a part of the Army story.”

However, it’s not anything goes: the guide warns that when using social media, soldiers must:

• follow the Uniform Code of Military Justice (effectively the body of law that specifically governs those in the military);
• maintain security by avoiding ” mentioning rank, unit locations, deployment, dates, names, or equipment specifications and capabilities.”
• never geotagging photographs;
• not use location-based social networking applications while on deployment; and
• not use copyrighted material on social media sites.

The guide also gives some further tips such as setting all social media accounts to the highest level of privacy setting, reviewing all pictures for potential security risks before uploading, and making sure family members know what they can and can’t mention in online postings.

There’s also specific advice for those in command positions, including a warning that “if you wouldn’t say it in front of a formation, don’t say it online”, and a suggestion that senior-ranking soldiers should not befriend or follow subordinates unless they are using social media in a purely professional capacity. (The logic appears to be that no soldier should see what his or her sergeant got up to on Spring Break all those years ago.)

There’s also a warning to Army communications staff that social media is not a one-way medium: “Answer questions as often as possible… Listen to what the audience is talking about and be prepared to engage. This is the best way to stop rumors before they run rampant.”

And in case you’re wondering, yes that is a genuine image from the guide. And if you’re tempted to comment on the photo editing skills involved, just remember: these dudes have big guns.