Whoever conducts the background check should work from a list of information the employer has predetermined that they want to find, which can be both positive and negative attributes. The researcher can then print or copy the materials they have found and bring them back to the hiring organization; omitting any information that is illegal to use in a hiring decision. This ensures hiring personnel do not have access to protected information, said Mavis.

"Just because someone puts it on a blog or Twitter, doesn't mean it's true," said Hyman.

While information uncovered during a background investigation using Facebook, Twitter, blogs or other online sites, may make a candidate seem like a poor fit, it's important to follow up and let them know what you have found.

"If you decide not to hire a candidate based on something a researcher has found, present them with that information, explain why it's a concern," said Mavis. "There is always a chance it's incorrect on social media. It could even be the wrong person. But the candidate deserves a chance to explain."