I think some people have had this question, but I couldn’t find anyone who had this query. Let me cut to the chase.
Suppose you don’t want people to know that you’re active on Facebook. Say, your boss is ‘Friends’ with you on Facebook and you don’t want him to know that you’re active online. At the same time, you don’t want to compromise with your ‘Virtual Social Life’ either. So, you’re browsing through the contents on your News Feed. An old school friend of yours has shared a very awesome picture of some place he went for vacation and you want to ‘like’ it or ‘comment’ on it. So you go to see the privacy. It is “Friends Only”. Okay, so if you hit the button here, you’re still out of your boss’s reach, because you know that these two people are not ‘friends’. You post your comment. “I wish my boss grants me leaves so I can go some place too! Boy, he’s a terrible human being, my boss! Blah Blah…”
Now a day or two later, your friend thinks “Hey, this is an awesome picture. It’s not from my intimate family pictures either. I must share it with the world!” And he sets the privacy to “Public”
Whoosh! That’s the sound of your promotion being dumped down the window once your boss sees your comment.
However, there is the option to screen your activity from certain ‘Friends’, so you may enable those. Facebook is refining this aspect of the social network vigorously. They will come up with some brilliant solution in time. Nevertheless, if the stakes are too high,take this piece of advice-
No matter what, be careful about what you say online.