In 2013, California and Illinois joined Michigan, New Jersey, Maryland and Delaware as the states which disallow employers from requiring you to provide your username and password to your social media accounts when applying for a job. Since Congress hasn't been able to pass the Password Protection Act of 2012, these six states have taken it upon themselves to protect the privacy of their citizens.
Of course, this rule only applies if your account is private. Public accounts are a different story.
[via CNET]