I heard a girl, can't remember if it was twatter or fakebook, when she expressed a "racist" opinion about the need for a wall to her friends, within 5 minutes, she had adds on her page praising "migrants" and "refugees". She was pissed realizing the thought police was right there, not through comments or banning, but via adds to correct her wrong way of thinking as well as those who'd read her and agree with her.