"You would never ask on a job application what year someone graduated from college, because that could disclose how old someone is," noted Hyman."That is not something you want to know when making hiring decision. But if you go on Facebook, you can see what year a person graduated, and you can easily put two and two together and figure out something that is information you would never ask for otherwise."

Having an independent researcher, someone not linked to the hiring and recruiting process, look for information and report back to you may be the best way to avoid any impropriety on the part of the hiring organization, said Mavis.

"If I can access your Facebook profile, I can see your sex, your age, your race. All that is privy to me and I can't realistically say I didn't have access to it," she said. "But as a researcher, I could have access to it. I just dont report it on to the hiring managers."

An independent researcher does not always have to be someone outside the company, said Mavis. Smaller organizations that may not be able to afford to hire a third-party can recruit an employee within the company who has no influence on the hiring decision.