I just read about a young employee who posted a negative message about her employer on Facebook, it was discovered by management, and she was called on the carpet for it and given a warning (apparently they didn't have a policy). Instead of seeing the bigger picture and learning a valuable lesson about tact and discretion, the employee wrote a long, rambling, accusatory letter to her boss which concluded with her resignation, and then she (wait for it) posted it on Facebook. She'll certainly have a difficult time getting another job, and may even end up in a lawsuit, but it points to the need for employers to have social media policies.

So - does your place have such a policy, and if so, what does it say?