You are personally responsible for what you say and post on social networking services and any other medium. Consider how a post can be interpreted by the public. Be cautious about crossing the line between funny and distasteful. If you have doubts about whether you should post something, err on the side of caution. Maintain appropriate communication and conduct with officer and enlisted personnel, peers, superiors and subordinates (to include civilian superiors and subordinates).
Social networking sites allow people to interact with others and find people with similar interests or backgrounds. These sites enjoy worldwide popularity, underscoring the need to understand potential risks associated with the use of these sites. A person’s online activities may inadvertently expose excessive information about their identity, location, relationships and affiliations, creating an increased risk of identity theft, stalking, or targeted violence.
Assume that once something is posted to Twitter, and by extension the Internet, no amount of effort will eliminate it. The Internet does not forget. There are sites that collect Twitter content and keep copies of Tweets on searchable servers. Because of this, anyone, whether they have a Twitter account or not, can see your Tweets.
Facebook has many options available that allow various levels of access to your account. Consider setting trusted contacts, limit who can look you up, set login. alerts, and enable two-step verification when logging in.
Do not post classified or sensitive information (for example, troop movements, force sizes, weapons details, etc.) If in doubt, ask. Security is at the source. Pay attention to what’s in the background of photos/videos