George’s Employment Blawg, written by attorney George Lenard of St. Louis, has some excellent posts (see here and here) on the risks and liabilities associated with using Facebook for employment background checks.   Some of the risks may include discrimination claims and Fair Credit Reporting Act violations.  The use of other social networking sites such as MySpace have similar considerations. 

[Lenard] would advise employers to cut applicants and employees some slack. You were once young too and maybe did similar things — if not publicly on the Internet. Ask yourself how relevant the information creating the negative impression is to job performance.

If you are going to do Internet searches and use them as a basis for employment decisions, you better do so consistently, without regard to any legally protected classifications, e.g. race, sex, age. You should document them.

I would add that if employers intend to conduct background checks of any kind for prospective employees it is important to have them sign a release and authorization allowing you to conduct background checks.  In Iowa, many employers are using the Iowa Courts Online to conduct free background searches.  Using the release and authorization may make it safer from a legal standpoint but you still must be aware of discrimination and Fair Credit Reporting Act issues when using these online resources to conduct background checks.

It is also advisable to consult your employment lawyer before using these online resources.