This analysis of the Leave campaign raises a very disturbing point (start at 02:50 if you want to fast track to this):
Who pulls the strings behind Brexit?
The thing that made this campaign different was the Dark Advertising funded by Dark Money: where ads, funded by money of unknown provenance, were only seen by the sender (obviously), the social media platform (Facebook) and the targeted recipient.
The principles of an open democratic campaign totally subverted .. I know that members on this forum who believe in Democracy would wholeheartedly condemn this.