The National Labor Relations Board’s recent decision in Costco Wholesale Inc., invalidated certain personnel policies, including social media policies, protecting the dissemination of employee health information and personal identifiers. This case marked the NLRB’s first decision involving its independent General Counsel’s interpretation of federal labor law as it applies to social media and other personnel policies. The decision (profiled here by Joel Barras) signals the NLRB’s agreement with its chief prosecutor’s attack on commonly adopted policies regarding, among other things, confidentiality of company information, and follows the series of reports issued by the NLRB General Counsel on social media.