Of course Farage has form over this.
Cambridge Analytical -one of whose founders was Steve Bannon, a notorious white supremicists and a friend of Farage - was employed by Leave EU of whom Farage was head.
Cambridge Analytica did exactly the same thing by using data illegally obtained - it was used to target individuals in the run up to the referendum. No one knows how much influence this might have had, but we do know that it was entirely illegal.
Farage, it seems is doing the same again, as this site was set up about two years ago and has been operating undetected since.
He will of course gasp in horror when challenged and immediately sort the issue out - but he is a slippery liar, constantly operating on the fringes of legality, particularly where he is using his influence to cause discontent and the Farage riots.