"Employers need to ensure that the ground rules of acceptable behaviour online are firmly established"
I agree with this statement, but not in this case.
The Civil Serf is either a very clever player, or a very stupid one. Calling your management idiots in public is what is known at some companies as a CLM (Career-limiting move). However, the degree to which it happened in this case would make it a cut-and-dried termination offense in my book. Surely she didn't think she'd remain anonymous for long?
Something she may not have thought about: would *you* hire someone with a mouth that big after she's fired?