Social media interactions are:

a$.$

usually protected by Section $7$ of the NLRA because employees have the right to discuss their terms and conditions of employment with their coworkers.

b$.$

not covered by any major labor relations legislation because they were enacted well before the internet was even created.

c$.$

only protected if the employer does not have a social media policy.

d$.$

monitored by a division of the NLRB and if an unfair labor practice is detected then the NLRB will send a warning letter to the person or company who participated in the unfair labor practice.