A while ago I have closed my Facebook and Linkedin accounts. These services were simply not bringing me any value. Apart from that, I don’t like the way they operate by gathering as much data about me as possible (for example when you install an App on your phone, it tries to upload your entire address book with names, phones and emails to a remote server) and manipulating what they show to you (payment-driven newsfeed, targeted ads).
It doesn’t mean that I’ve given up social networking altogether though. I am following very interesting federated social networking standardisation initiative at W3C Social Web Working Group, chaired by Tantek Çelik (of Indie Web Camp) and Evan Prodromou (of pump.io).