Many employers nowadays have a social media policy for their employees. But they may not know that the National Labor Relations Act protects “concerted” speech & activity by their employees. This means that employees can talk about their work environment including talking about other employees, their boss, or how much they make.
This provision in the National Labor Relations Act applies to non-unionized work places as well as unionized ones.
Employers have a legitimate right to protect trade secrets and confidential information of the company and its clients. However employees do not have the right to restrict all workplace related speech by their employees.
Employees can abuse the privilege by posting comments that are violent, slanderous or otherwise unlawful.
From the article “Office Talk” by Michael Melder and Justin Jeter- Texas State Bar Journal February 2015, page 178