Here are four common social-media moves that could get your company in hot water.

1. Too-broad restrictions. Like it or not, employees often have the right to complain about work or wages on social media. To avoid National Labor Relations Board ire, clean up any wording in your policy forbidding employees from discussing all work-related matters on social networks. One suggestion: Include examples of what is permissible.

2. Muting whistleblowers. Your employees are permitted to talk to the media or to federal agencies, including the Occupational Safety and Health Administration. The NLRB will have a very strong case against your company if your policy says all such communications must first be approved by a manager.

3. Dated guidelines. Despite the NLRB's social-media crackdown, a Grant Thornton study revealed that as of last September, almost 25 percent of companies that had social-media policies hadn't updated them in the past 18 months. "Many times, we find a disconnect behind policy and practice," says Mark Sullivan, of accounting firm Grant Thornton. "The company writes a great big policy, and it sits on a shelf"-and then is ignored or forgotten.

4. Friending subordinates. Aside from awkwardness, social-media friendships with subordinates can create a potential legal minefield should discrimination or harassment accusations arise. Labor lawyers say there's a rise in employees' claims over missing raises or promotions because of a boss's reaction to something posted to Facebook, Twitter, or Instagram.