This will prevent Jacob from sending you messages, friend request or from viewing your profile. They will not be notified. Comments on discussion boards from them will be hidden by default.
“I be crazy too, little buddy, but at least when I be craziest, I be floating all alone in space and the crazy, she float out of me, she soak into the walls, and she don't come out till there be battles and little boys bump into the walls and squish out de crazy.”
―
Orson Scott Card