private messages can be good or it can be bad too. We can’t surely say it as an advantage. If doing private message is an advantage then this feature would be implemented on stackoverflow. I was in mental pain for almost one and half year due to this private message thing here. There is a high chance that two unknown person will be in the circle and then start discussing questions and then they come to facebook, whatsapp etc. and then attachment, frustration, irritation and there are so many things can happen. I have gone through it and have seen similar thing with Habib sir in a post in the facebook group of GateOverflow previously and so, I don’t believe in private messaging while preparing for any competitive exam (People might have different opinions also.) It is always good to discuss questions publicly in comments or chat room might be added if there were so many comments.