&gt; Google are not the only player in this area though, I suspect that Facebook can also reliably influence enough people.<p>Facebook have published research in this area of emotional manipulation through their news feed: <a href="http:&#x2F;&#x2F;www.pnas.org&#x2F;content&#x2F;111&#x2F;24&#x2F;8788.full" rel="nofollow">http:&#x2F;&#x2F;www.pnas.org&#x2F;content&#x2F;111&#x2F;24&#x2F;8788.full</a><p>&gt; We show, via a massive (N = 689,003) experiment on Facebook, that emotional states can be transferred to others via emotional contagion, leading people to experience the same emotions without their awareness. We provide experimental evidence that emotional contagion occurs without direct interaction between people (exposure to a friend expressing an emotion is sufficient), and in the complete absence of nonverbal cues.