This NYT article argues that the use of social networks like facebook or orkut is similar to social customs that existed among humans during tribal times. Excerpt:

Michael Wesch, who teaches cultural anthropology at Kansas State University, spent two years living with a tribe in Papua New Guinea, studying how people forge social relationships in a purely oral culture. Now he applies the same ethnographic research methods to the rites and rituals of Facebook users.

“In tribal cultures, your identity is completely wrapped up in the question of how people know you,” he says. “When you look at Facebook, you can see the same pattern at work: people projecting their identities by demonstrating their relationships to each other. You define yourself in terms of who your friends are.”

Read full article. Quite interesting.