In Exodus 33:11 we read that "the LORD would speak to Moses face to face, as a man speaks with his friend." I think face to face friendships are closer than Facebook friendships. (Many have commented on the use of "friend" on social networks like Facebook, usually admitting that Facebook "friends" are, mostly, different from face to face friends.)
In John 15 Jesus calls his disciples "friends." The Greek word here is philoi, which is from philia, one of the four Greek words for "love." Jesus' words "I call you friends" could be translated as "I call you the ones I love." Philoi has nuances of intimacy that our English word "friend" does not capture.
My son Dan and his wonderful wife Allie are in their second year working in Japan. It's been a year since we have seen them. Linda and I do appreciate Facebook because we pull up pictures they post there. But better than that is when we talk with them on the phone. Best of all will be this coming April when they return home after two years away and we will see them, face to face, and hug them.
No doubt, social networking is huge and will only get bigger. It surely has its positive aspects. It is also transforming the traditional idea of "community" as a face to face, actual physical-presence kind of thing. Hence, for me, arise some concerns, and some cons of social networking. One "con," e.g., may be: "The hours per day of face-to-face socializing have declined as the use of social media has increased. People who use these sites frequently are prone to social isolation. Parents spend less time with their children and couples spend less time together even when they live in the same house, because they are using the Internet instead of interacting with each other." One "pro" of social netowkring may be: "Social networking sites allow people to create new relationships and reconnect with friends and family. Increased communication, even online, strengthens relationships."
Surely many examples of the blessedness of social networking can be given. And yet, as cited above, I have concerns over some parents who seem to dwell on Facebook, making me wonder about them and their marriages and families. Some Facebook-prophets are needed to call these faces back to the land of physicality.
Surely a strong case can be made for the superiority of face-to-face rather than Facebook when it comes to friendships. One wants to hold the beloved in one's arms rather than merely touch the screen. Because persons are psycho-physico-spiritual beings, the most meaningful way to engage and potentially befriend real persons must include physical presence. Even though the days of Facebook text-weddings is coming, it's a lot better to physically kiss your life partner standing before the presence of family and friends.
For a good list on the pros and cons of social networking check this out.