An important finding, Ms. Ellison said, was that students who reported low satisfaction with life and low self-esteem, and who used Facebook intensively, accumulated a form of social capital linked to what sociologists call “weak ties.” A weak tie is a fellow classmate or someone you meet at a party, not a friend or family member. Weak ties are significant, scholars say, because they are likely to provide people with new perspectives and opportunities that they might not get from close friends and family. “With close friends and family we’ve already shared information,” Ms. Ellison said.