We've heard of the job applicant who misses out because their face is all over Facebook in embarrassing positions. Similarly there's the worker who Twitters what a great time they're having at the cricket when they're on a sickie. Then there's the blogger who's spotted writing how much they hate their boss.

The dangers of social media in the work place are well documented. But now comes a warning that even the benign career networking site LinkedIn can land workers in hot water.

A Canberra interior designer was sacked from his day job when his boss found he was using LinkedIn to connect to potential clients for his small out-of-hours business. The designer was fired after he sent a group email via LinkedIn saying he planned to expand his fledgling business to a full time design practice.

Even though his employer allowed him to work in his private capacity on smaller jobs outside work, the Fair Work Commission ruled the employer was within its rights to fire him as he was soliciting work that could be in competition to his employer. The case highlights the lesson that what people post on social media isn't necessarily a private matter that has nothing to do with their employer. Always ask yourself before you post, tweet or email something whether you'd be happy for your boss to read it.

Kym Luke, employment law specialists at Stacks/The Law Firm, says employers should take note. "There's a need to set clear guidelines for employees on the use of social media in the workplace," Kym said. "If they have a small business on the side or work somewhere else casually, there should be an unambiguous policy spelling out what the employee can and can't do. "

Employees have to be informed of the consequences if they do something on social media that might conflict with their employer, or brings their company into disrepute.

Some employers might want to simply ban using social media in the workplace, but this might not be beneficial in businesses that benefit from employees networking and building work contacts through social media.

What happens when an employee who built a large social media network while with the company leaves to set up on his or her own? Can they take the social media contacts with them? The courts are generally deciding this on a case by case basis. Employers need to get good legal advice to put in place a social media policy as it applies to their particular circumstances, including ongoing obligations for departing employees.

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