They follow up on recommendations. They - actually read the book you raved about at a party - actually listen to the podcast you mentioned during lunch - actually read the article you sent them on Whatsapp - actually watch the movie you love to brag about Why? Because learning about the world feels viscerally good to them. And every recommendation is a map with a potential hidden treasure. That great next idea to explore is hidden where you're not looking. And a recommendation gives you a way.