Recently, there was an ASKREDDIT thread about individuals sharing their stories of being fired over social media posts they made. The stories are interesting, but it leads me to a philosophy I've was given by my mother many years ago; "If you're not willing to publish it on the front page of the NY Times, don't write it."
It's a very simple idea of which I try and abide to as best I can, though I'm not perfect. There have been many posts or responses I've deleted before posting, and I'm sure a few slipped by my better judgment.
The idea that discretion as an employee is just as much a goal as the face of a large corporation should not be taken lightly. This is exactly why we recommend having an audit done of social media exploits concerning individuals and organizations. There are many tools now that allow for scanning of public posts by geolocation, some of which can show safety concerns. For example, if a person working in a refining plant is taking a selfie smoking a cigarette in a non-smoking area, this can be alerted and handled.
In the day of information, an organization or individual cannot be too safe. It's best to know what is going on and deal with it appropriately, rather than a large customer or prospect finding it first and turning away business.