How many Social Networking sites is enough?

I find myself feeling a bit overwhelmed by the amount of invitations to join social networking sites. I wonder how many people really want to be there at all. Truth be told that if I had a choice I probably would use it a lot less than I currently do. The only reason I joined FB was...so I would have something to blog about. No really, if it was not for my field of work I would probably not be engaged with this technological world to the extent that I am. For this reason I do feel for those who still find themselves on the outside looking in.

Belonging to Social networks can become very time-consuming if not managed properly. "Just change your security or privacy settings to something that suites you", you say. But why should I have to be bothered by all that? Why can't SNS's not just start off by respecting my privacy as a default and then leave it up to me how much about myself I make available? Ok so this might not be true for all SNS's but just let me vent for now. So now I am on FB, Twitter, Linked-In, Google+, Chime-in, and few others that I've just comepletely forgotten about. So remind us about finding a healthy balance here is a light-hearted look at twittering.