Indicating its continued interest in the application of workplace social networking policies, the National Labor Relations Board (NLRB) announced last week it would issue a complaint against Thomson Reuters Corp., alleging the company violated federal labor law, specifically § 8(a)(1) of the National Labor Relations Act. The NLRB apparently plans to allege that Thomson Reuters interfered with, restrained, or coerced employees in the exercise of their § 7 rights, which section permits employees (whether or not they are represented by a union) to engage in protected concerted activities to improve working conditions, such as wages and benefits.

Allegedly, Thomson Reuters verbally reprimanded Deborah Zaberenko, one of its reporters, for sending a tweet to the company stating, “One way to make this the best place to work is to deal honestly with Guild members.” The NLRB alleges that Thomson Reuters implemented an unlawful social media policy that chilled employees’ § 7 rights, and that it improperly applied that policy to Zaberenko following her tweet.

This will not be the NLRB’s first complaint about a workplace social media policy. In October 2010, it issued a complaint against American Medical Response (AMR) for what the NLRB viewed as an improper application of an overly broad social media policy. AMR had, at the time, a social medial policy that prohibited employees from making “disparaging, discriminating or defamatory comments when discussing the company or the employees’ supervisors, co-workers and/or competitors.” It disciplined one of its employees after she posted disparaging comments about her supervisor on her personal Facebook page following a disciplinary meeting. The NLRB took the position that AMR’s policy, standing alone, may interfere with the employee’s right to engage in concerted, protected activities.

Because the AMR case ended with a settlement, the NLRB never came to a definitive pronouncement about the legality of that particular policy. We may see such a pronouncement in the Thomson Reuters case, but, in the meantime, employers eager to implement such policies must tread carefully when doing so.