Prankster Shows His Knowledge of Complete Strangers in Ultimate Social Media Joke [VIDEO]

You may want to think twice before you post something on social media.

In this video, filmmaker Jack Vale decides to play a little experiment in which he looks through the Twitter and Instagram accounts of people near him. Then, he approaches these complete strangers and scares the heck out of them out by telling them information about themselves they've plastered online.

Moral of the story: be careful what you make public because you never know who is looking.