The problem with social networking sites is not who's on them. Ramanand would disagree, but most people on my friend list are pretty considerate with their messaging and so on.
The problem is who's not on them. For every person on my network I kind of knew back in the various institutions I was part of (pun intended), there are an equal number of people I knew really well who are not on any of the networks I've been suckered into joining. I know digital junkies who read blogs will find it surprising, but there are people who disappear off the face of the online world. Inspite of being well-educated and computer savvy.
Close friends, especially from way back when the Internet was just pie-in-the-sky for us ordinary dehati Indians, have since shifted cities. Lost addresses, dropped correspondence and life have all taken a toll of these ties.
Talk with friends from then tends to gravitate towards "What is X up to nowadays?" with the answer invariably being "His parents shifted, and we lost touch. Last I heard..."
Bygones are bygones. The past is past. But friends are friends. The good kind are hard to come by.