More and more employers are using social media as a hiring tool. They can base their decision to hire you or not on what your social media interactions reveal. Honestly, even if you're not concerned about a potential employer, it's still a good idea to think before posting to Facebook or Twitter. Remember, once you put it out there… it's out there forever.
I mean, really, do you want to have something you said in a moment to come back and bite you in the butt???