A giant ''like'' icon made popular by Facebook is seen at the company's new headquarters in Menlo Park, California.
Never mind what you write about on Facebook, simply clicking the 'like' button could cost you your job.
Six workers in the US were fired for 'liking' the Facebook page of their boss's political opponent after a federal judge ruled that clicking the 'like' button is not constitutionally protected speech.
Unlike in the US, the right to free speech is not enshrined in the Australian constitution, and people here have already lost their jobs because of comments made on social networks.
Last year roads worker Alec Armstrong was sacked after commenting on Facebook that the council had too many office staff and not enough workers. Jane Morgan was fired from her job at a construction management company in Sydney in 2009 after she wrote a message on a friend's Facebook wall saying the company "sucks".
"People don't go to the pub and talk to a few mates anymore, they get on a computer and talk to 10 million people, so they need to be that much more careful," says Robin Young, a partner at the Sydney-based law firm Holman Webb.
Mr Young believes that coming out against the company in the public domain can be reasonable grounds for dismissal.
"If a person who was a senior lobbyist for a politician was found to be supporting the opposition, then some people wouldn't be surprised that that person may be sacked from that role."
But does the act of merely clicking a button on a website constitute fully fledged support of the opposition?
"Whether or not it's justifiable to terminate them solely for liking the opponent candidate on Facebook, I think is a very long, almost quantum leap," says Young.
In the case in the US, Sheriff B.J. Roberts of Hampton, Virginia, fired six of his staff members for liking the Facebook page of his running opponent in the 2009 election.
He said that their actions had "hindered the harmony and efficiency of the office".
The staff members sued, claiming that their First Amendment rights had been violated.
However, Judge Raymond A. Jackson of the Federal District Court said in his ruling that clicking the "like" button did not amount to expressive speech.
Essentially, because there was no actual writing or speech involved, the act of clicking a button is not afforded constitutional protection under the ruling.
Judge Jackson conceded that other court rulings have acknowledged Facebook posts as protected speech, but said that those cases had involved "actual statements".
"Simply liking a Facebook page is insufficient," he wrote in his ruling.
A lawyer for one of the workers said he would appeal Judge Jackson's ruling.
The solution? A clear and reasonable social media policy within companies, says Young.
"If you have rules and policies about social media and how it's to be used, then there can't be any doubt about how people are supposed to behave."
A reasonable policy would call on employees to exercise discretion and restraint, especially in matters concerning their workplace. A policy that banned workers from Facebook altogether, at work and at home, would not be reasonable and would not be likely to stand up in court.
But a social media policy in the workplace is not a blanket fix for the issue. Both companies and their employees must act reasonably and respectfully.
"Employees have to expect that their employers are going to see what they're saying on Facebook," says Young.
"Notwithstanding privacy settings, what is said may be conveyed by others to others and the first person has no control over what happens once it's out there."
The law remains murky around communication via social media, but in the meantime, be careful what you click on.