People often trust their social media contacts more than traditional advertising, and more readily believe everything from restaurant reviews to political opinions when it comes from a social network. An amusing or tragic anecdote that may not be representative of any trend has a better chance of going viral than a well-reported story with lots of analysis and facts. As always, there are marketers, abusers, propagandists, and outright criminals who are quick to exploit these psychological biases. The person who attacks you over a political tweet may be a paid troll or a robot. The spam you ignored in your inbox is now served into a trusted social media feed. The phishing attacks and malicious links you’d never click on in an anonymous email may now appear as a recommendation from a good friend, or a celebrity you admire. These attacks may even be customized by AI to target you perfectly, the way you get shopping or movie recommendations.