The National Labour Relations Board (NLRB) says it has been getting an increased number of social media cases as that means of communication continues to grow in popularity.The resulting actions against employers and employees should be a warning both to companies trying to restrict social media postings by employees and to workers who use the medium to air their grievances.In one recent case, the board ruled that a non-profit in New York state could not fire employees using Facebook to share criticism of their working conditions.The issue started when an employee at Hispanics United of Buffalo, which provides social services to low-income clients, posted on her Facebook page comments that a co-worker had made about other employees, saying they were not doing enough to help the organisation's clients.The employee who put up the post then solicited feedback from other co-workers, according to the labour board.Some of the postings that followed contained profanity, but they mostly criticised working conditions, including workload and staffing issues.Upon seeing the postings, the co-worker who had made the criticism said she considered the Facebook conversation to be “cyber-bullying” and “harassing behaviour,” a board report said.In the end, the employee who posted the comments and four workers who responded were all fired. Hispanics United claimed the Facebook conversation constituted harassment of the employee whose criticisms were noted in the original post, the NLRB said.But an administrative law judge for the board ruled that the employees' Facebook discussion was protected under the National Labor Relations Act because it involved a conversation among co-workers about their terms and conditions of employment, including job performance and staffing levels.The judge ordered Hispanics United to reinstate the five employees and give them back pay.Section 7 of the National Labor Relations Act protects the “concerted activities” of workers who engage in discussions about the terms and conditions of their employment.The rule stems from union organising, but now it's increasingly being applied to protect workers talking via social media, said David Scher, a principal with the Employment Law Group law firm in the District of Columbia.Scher says workers' criticisms of their employers on social networking sites are generally protected and employers may be violating the law by punishing workers for such statements.“A knee-jerk reaction by an employer to a comment an employee makes in social media could create liability for the employer,” he said in an interview.The labour board found in the Hispanics United case that the Facebook discussion was “a textbook example of concerted activity, even though it transpired on a social network platform.”But likewise, Scher said, employees shouldn't think they can just post anything about their job situation.Workers need to make sure that they're not making comments that are outside the scope of the law.Divulging confidential information or defaming a manager could lead to termination.“If I go online and say, ‘My boss is a jerk,' that probably is not protected,” he said.“But if you say, ‘My boss is making my working conditions unbearable,' that is probably protected.”In August, the labour board's general counsel's office released a report detailing the outcome of more than a dozen cases involving the use of social media.In four cases involving employee use of Facebook, the board found that the workers were engaged in “protected concerted activity” because they were discussing terms and conditions of employment with fellow employees.The board found that in some cases, provisions of employers' social media policies were found to be unlawfully too broad. In another, the board ruled in favour of an employer's policy restricting its employees' contact with the media.In one case, it was determined that a union engaged in unlawful coercive conduct when it videotaped interviews with employees about their immigration status at a non-union job site and then posted an edited version on YouTube and the local union's Facebook page.But it's important to note that in several cases involving Facebook or Twitter posts, the social media activity by employees was not protected.Scher says his firm advises its clients to “say nothing in social media about their employers, because we don't want our clients to inadvertently make a mistake.”I know it has become common to share your every thought or feeling about every aspect of your life on Facebook or Twitter, but ask yourself before you hit the send button if a particular posting or tweet about your company or your co-workers is really worth the possibility of losing your job.Readers can write to Michelle Singletary c/o The Washington Post, 1150 15th St, NW, Washington, DC 20071. Her email addressis singletarym[AT]washpost.comComments and questions are welcome, but due to the volume of mail, personal responses may not be possible.Please also note comments or questions may be used in a future column, with the writer's name, unless a specific request to do otherwise is indicated.(c) 2011, Washington Post Writers Group