A teacher also complained she was disciplined over comments she made about being bullied. But Steven Penning, a partner with Turner Freeman with two decades of experience in workplace law, says employers may be acting unlawfully.

He said employment contracts are unlikely to cover staff use of social networking sites. --------------------------------------------------------------

MashUp Blog: Have you been threatened over social network comments?

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"What employers are doing is they're scrambling and trying to make out that present policies can be stretched to cover these new areas, and in many respects they can't," Penning said.

"If an employer hasn't told people in advance what the rules are, what the conditions are, then that greatly increases the likelihood that an employee can say well, I can't be terminated for this because I wasn't aware that this is something I was not to do." He contrasted this with the clear policies surrounding the use of work internet access and email that staff were made aware of as soon as they signed up.

The growth of social networking sites like Twitter, Facebook and MySpace has meant people are having private conversations they would have at the pub in an online setting. However, Penning said this was no longer considered private comment because the discussions are published and distributed publicly. A 27-year-old Australian woman, who did not want to be named, said about six months ago her employer - a large online technology company - started disciplinary action against her over a "generic" comment she wrote on the Facebook wall of a friend, who did not work at the company, outside of work hours.

She said she wrote something along the lines of "he's such an anally retentive asshole", without naming any individuals or the company. A manager at the company thought the comments were referring to him and refused to back down on giving her an official warning, so she quit her job. She claims she was "managed out" of the company, which went on a "witch hunt" and manipulated her comments to suit its own agenda.

"There should be some sort of transparency with regards to what you can do and what you can't do ... employers should not be using Facebook or MySpace or Twitter for their own management issues or to try and find dirt on their employees," she said. Yesterday, this website revealed the NSW Department of Corrective Services is threatening to sack prison officers over posts they made to a Facebook group criticising the cash-strapped State Government's plans to privatise Parklea and Cessnock prisons. It comes after a Telstra employee Leslie Nassar was reprimanded for comments he posted on his blog and Twitter.

Penning said most employment contracts and policies had rules against speaking to media, but these were different from posting comments on social networking sites. "The first thing that needs to be done is a thorough audit of all of their policies, employment agreements and contracts to determine if those documents refer at all to social networking controls and social networking obligations, and that's the first step," said Penning.

"It's not about total control ... it's saying that you're not using the sites or saying things on the sites which are damaging to the organisation that you work for." Penning cited the example of three scantily clad Californian teens who were fired from their jobs at KFC late last year for publishing photos of themselves on MySpace bathing in a KFC basin. "Something like that is damaging and has the potential to be very detrimental to an organisation, because it's clearly saying it's not healthy to eat here, our standards are appalling," he said.

A reader responding to yesterday's story about the NSW prison officers said he was fired from his job at a "large corporate bank" for using the word "recession" in his Facebook profile. "Ended up being reprimanded by both my boss and the head of our division, despite not using the company name or having either of them on my friends list. I lost my job shortly after," the reader wrote.

Another reader said they published a comment on MySpace about being bullied by a colleague, but inadvertently made it public when it was intended to be a private message to another colleague. "I received a call from the principal of the school (I was a teacher) 6 weeks after I left my position letting me know that over 400 people had seen the message (including students and parents) and I needed to come back to address the matter," the reader wrote. "I spent 5 years working at the school and I won't ever get a reference now ... Everything is public once you put it on the internet."