From Urban dictionary I verified that "PM me" means "private message" me. I thought "private message" is a verbing noun and it usually appears in group chat rooms where many people can see the message we send. When someone in the group decides to initiate a point-to-point channel with some particular guy also in that group s/he would say "please PM me" which means "let's have a private talk". Am I right?
What if two people are discussing something in a private channel(one to one) and one of them is vexed by something and doesn't reply to the other guy for a long time and the other guy says "please IM me when you are free" where IM means "instant message".
I found the sentence below from here.
If Mike comes online, tell him to IM me.
Do native speakers say that way?