Illinois Gov. Patrick Quinn signed the amending the state's existing 'Right to Privacy in the Workplace Act,' into law last week.

The amendment goes into effect Jan. 1 and makes it unlawful to "request or require any employee or prospective employee to provide any password or other related account information" to any social media networks to which they might belong.

The bill does not limit employers from lawfully monitoring employee computers and emails. Nor does it limit them from seeking or reviewing publicly available information about a person from social media sites. The ban on access to worker's social media profiles applies even in situations where a job might require comprehensive background screening.

Illinois follows Maryland and Delaware in passing such a law. Several other states, including California, Massachusetts, Michigan, New York and Washington are considering similar legislation.

The laws are being prompted by what some see as a disturbing trend among employers and educational institutions to ask current and future workers for access to their social media profiles as a condition of employment.