Girls are definately way too mean to eachother. They will spread rumors behind eachother's back just because of a guy or because of something they think their "friend" said. They feel the need to get back at eachother for ridiculous reasons.
Social networking most definately brings people together. If it weren't for networks such as Facebook or dating websites such as eHarmony, there are people in the world that would not be married or not be friends, let alone even know who eachother is. Many good relationships have come from these dating websites, and a ton of friendships have been made as a result of Facebook.