I continue to wrestle with my relationship to such things. You can only have so many actual close friends. There are only so many hours in the day and close friendship requires sustained, on-going interaction to maintain. For this reason, I tend to think "social networks" are doomed to be shallow affairs. Yet, paradoxically, I find that I share a lot more info online than I do with most folks I know in person. I'm not shy there just isn't enough time in the day to explain some things to everyone I meet, so I just don't want to open up some can of worms. Still, I wrestle with this process where I seem to gradually be working on developing an online audience where the relationship is inherently lopsided: Other people often know a great deal more about me than I know about them. But this isn't really what I think of as friendship and I like having friends, which have been a tad scarce of late (remaking your life usually causes you to shed friends).
I don't have answers for you. Just sharing some of my own internal questions, FWIW.