Q: I've found a compromising YouTube entry for a senior manager at my company by accident. He uses another name but it's obviously him. I don't know this man personally but I can't believe he has been so irresponsible. I'm the HR manager at the firm. What do I do?
A: Let's accept you're right and it is indeed this senior manager. Then suppose for a moment that you'd never stumbled on this compromising entry. Knowing what you know now, what might the consequences have been: for a) your company; b) other individuals in the company; and c) the senior manager himself?
You don't disclose what it is that he's so irresponsibly revealed, but do you have good reason to believe that whatever it is - his nature or his behaviour - puts others at real risk? Do you believe him to pose a threat to the company's reputation? Or that he could have an adverse effect on colleagues? Or do you think that if other people were to crack his YouTube identity - you seem to have found it easy enough - it could be explosive?
If you can confidently say no to these questions, then I believe your decision is a pretty simple one. However much you may personally disapprove, as long as they affect no-one but him, his personal revelations should remain his personal business. It's no business of yours or your company's.
If, on the other hand, you're certain that his YouTube entry spells potential problems for others, then you've clearly got to do something. But now he ceases to be an HR problem and becomes one for senior management. Being scrupulously careful to distinguish between moral disapproval and a conscientious analysis of potential risk, you must take your concerns to your CEO. I'd strongly advise you to make careful notes before you go.
It would be natural enough if your CEO's first instinct was to side with one of his or her senior managers and challenge your conclusions - in which case you could easily be branded as a mischief-making busybody who snoops around social networks, digging up whatever dirt you can find and then making unfounded accusations. So keep it strictly factual.
Once you've registered what you know with your company's management, you'll have discharged your responsibility.