Online friendships, real or electronic?

Recently I did a report for my english class about the positives and negatives of social networking, and my teacher informed me that my perspective was unique for a common teenager. I wrote about the negativity and how computer time should be limited to shield youth from the negativity on the internet. Most people use Facebook for communication with distant friends, and family but does that leave them crippled, in a way from developing socially? I voiced my opinions on the topic of social development, and brought up the point that texting or "chatting" people on social networking sites can leave them not knowing how to interact with others as easily as those who are not on social networking sites as often, and can leave someone with online "friends" with whom they never meet in person. I'm curious to hear your opinions on the subject and maybe gain more knowledge on the topic.