No official law prohibits employers from searching social networking sites while conducting background checks of current employees or job applicants. However, legal experts warn employers to be aware of potential federal and state discrimination claims and invasion of privacy claims.
There are some concerns about the legality of checking social media profiles. Like many things, it isn’t so much checking the profile that’s the problem, it is what you do with some of the information you uncover in the process. For example, some profiles will give away a protected status that wasn’t apparent before (for example, a religious affiliation or national origin). This can open up liability if you reject the candidate. Social media provides a gold mine of information to use in employment lawsuits.
In May 2011, the Federal Trade Commission gave permission to run background checks of individuals' internet and social media history. This decision opened the door for social media professionals like myself to provide this service. According to the FTC, social media background checks are in accordance with the Fair Credit Reporting Act.
The Equal Employment Opportunity Commission reminds employers and HR that the same questions you cannot ask in interviews are applicable in social media background checks.
The best way to protect yourself is to obtain consent from all candidates you will review.