Final answer:
The passage's main idea is how technology and digital media have changed the dynamics of forming and maintaining friendships, as well as providing support and sometimes increasing loneliness.
Step-by-step explanation:
The main idea of the passage is that technology and digital media have transformed the way we make and maintain friendships. The passage describes how teens use social networking sites and texting to form new friendships, maintain existing ones, and present their identities. It also touches upon how digital social networks can offer support systems, but can also lead to increased loneliness. The passage further discusses how college programs try to combat loneliness through peer mentoring and the importance of social support for mental health. Overall, it highlights both the positive and negative impacts of digital interaction in personal relationships.