"Everyone has bad days at work; with every job, there is some measure of discontent. (Why else would so many people be looking at job-placement websites?) Yet, often, such dissatisfaction can galvanize you by creating the motivation you need to propel your career upward.
"Meeting a trusted friend for a happy-hour drink and exchanging war stories is one matter—while no promises of confidentiality are explicit here, it is safe to assume that your friend will not relate your woes to others. (If he does, he's no friend of yours!) To be similarly blunt and candid in email or the blogosphere is to enter a potentially dangerous gray area."
Privacy is important, so before you hit "send," remember that what you say online stay can stay around forever.