According to suveys conducted by the HR Daily Advisor, 44% of employers use social networking site like Facebook to examine the profiles of job candidates. 39% have actually checked these sites on their current employees.
When they find negative inofrmation, such as revealing photos or lewd conduct the potential for being passed up for a job or even fired is high. However, employers should be careful using this information when making hiring decisions. The negative information could lead to a discrimination claim.
Also, it is important to make sure the information you are discovering actually belongs to the individual you are researching.
In addition to hiring/firing descrimination suits, there have been cases of negligent hiring and retention; claims that indicate an employer has an obligation to take action when an employee expresses a record of violence on public forums.