Dropped off the Facebook of the Earth
When somebody tries to look up a friend on Facebook, only to find that they deleted their account without telling you, thus losing contact with them forever.
Mr. X: "Hey, I tried looking up John's profile but couldn't find it. Do you know what happened?"
Mrs. Y: "Yeah, he Dropped off the Facebook of the Earth."
Mrs. Y: "Yeah, he Dropped off the Facebook of the Earth."