The act of logging onto the social chatting program Windows Live Messenger (MSN) and setting your status as offline. This allows you to converse with only the select people you want, and prevents you from being talk-attacked by every single person on your contact list, or being bothered in general.
Delia - Hey Jerry, did Dave talk to you last night on MSN?
Jerry - No, he wasn't on.
Delia - Yes he was, he was just ghosting.
Jerry - Damn! He needs to stop doing that to me.