Product Placement Blog ➞ Applications & SoftwareSignal Private Messenger in Mr. Robot – Season 4 Episode 1 “401 Unauthorized” (2019)October 7, 2019 Sergey TV Show Hi! On Monday, October 7, I analyzed a TV Show and product placement was spotted: Signal Private Messenger in Mr. Robot – Season 4 Episode 1 “401 Unauthorized” (2019).Here are 1 image(s) below: