demagogue

I'm sure it's been used as long as the word ghost has, just with different meanings. The one in OP apparently refers to ignoring someone on social media. As if social media sociology deserves the recognition. =L

I've heard people using 'ghosting' in Dayz: i) get into firefight on a public server, ii) log out, iii) log in to a quiet server, iv) move to advantageous position, v) log out and log back in to the original server to surprise the enemy from the new, better position. One of the reasons people like to play on Private shards.

I'd never heard of the social media meaning of "ghosting" before. I assumed the new definition was the usage from the Riddick movies (where it means "killing people").