In an effort to control employees' activities on Facebook and Twitter, some U.S. companies have instituted social media policies that run afoul of labor law and infringe on workers' rights, according to a memo issued last month by the National Labor Relations Board (NLRB).

Policies that forbid employees from posting anything potentially “misleading” about the company online or tell employees to be careful about “friending” their co-workers on Facebook violate provisions of the National Labor Relations Act, which covers collective bargaining and employees' “protected activities” in the workplace.

Areas of focus include prohibiting or restricting employees from:

1. “Friending” other employees. Workers have the right to communicate with each other, so statements encouraging employees to “think carefully about 'friending' co-workers” are illegal.
2. Posting about the company. Under federal law, employees have the right to criticize their companies and how workers are treated, so a policy that broadly stated that a company's employees couldn't talk about the company is illegal. Employees also have the right to discuss legal claims they may have against their employers.
3. Talking about co-workers. Workers have the right to discuss wages and conditions of employment with others and each other, so a blanket prohibition over talking about co-workers was considered illegal.
4. Posting the company or other's trademarks, videos and pictures without permission. NLRB said that a provision completely prohibiting posting this kind of content on social media pages was deemed unlawful, while a policy urging people to “respect third party intellectual property” is legal.
5. Talking to the press. Employees have the right to talk to the press in certain labor disputes, so a blanket prohibition over talking to the media was considered illegal.
6. Talking in an indecent manner. An employee has the right to criticize an employer's labor policies and treatment of its employees, so a provision warning employees to “avoid harming the image and integrity of the company” was unlawful. However, blanket prohibition of harassment and bullying are acceptable.
7. Talking about inflammatory topics. Employees have the right to talk in a “robust” manner about working conditions, so statements even just encouraging employees to “[a]dopt a friendly tone” in online discussions were deemed illegal, as they could be interpreted as prohibiting this kind of discussion.
8. Using social media while at work. The NLRB indicated that completely prohibiting employees from using social media with employer resources or on employer time was unlawful, because employees have the right to engage in certain activities on the employer's premises during non-work time and in non-work.