besides the moral implications of why you don't want to give someone a social networking password, there's one main thing that companies can never win against, if argued properly.    since facebook allows you to message with others, these are private conversations. so an employer requiring access to your facebook, gives them access to your private correspondence. that alone should be enough to make a reasonable argument against it, even if one has nothing to hide.     there really is zero good reason for an employer to log in to your facebook. the only plausible reason is if a disgruntled employee leaks sensitive information...and even then they could contact facebook to have it removed rather than getting your password. with that covered, there is zero reason left. besides, there's more places on the internet than just social networking where an employee could possibly leak secret company information.     it seems to me like it's just an excuse for employers to be nosy. something like this would most definitely be abused more often than not. I just can't wait until a disgruntled boss with all the passwords slips up and goes on a facebook defacing spree or tells someones grandmother to go **** themselves and  gets sued.    I think it's all a cover though, they say private messages aren't their concern, but that's exactly what they're aiming to get at. so that way they have leverage over their employee's. it'll go like this...     so and so has a pre-existing condition he was discussing on facebook private chats, that he failed to mention to the company insurance provider then they can just keep hush hush and let him keep paying into the system, but then when he needs it, say after getting severely injured at work, they can deny him for breach of insurance contract.     or so they can find dirt on their employee's (who doesn't have some dirt?) and use it as leverage to either fire them, or keep them at low pay or do things like make them 'volunteer' to come in on their days off without overtime pay. and since they know the economy sucks and it'd be hard to find another job, they have even more leverage.