My mother is a doctor. She lives in China and specializes in meningitis. In late 2018, she traveled to a conference in Chicago. By pure chance, she met a physician there who lived in Dubai. The connection they made enabled them to exchange information and insight and to develop a shared social knowledge base. Had they not met that day in Chicago, it's likely they never would have met at all. They met because the conference in Chicago brought them together around a shared interest.