Sherry Turkle, Professor of the Social Studies of Science and Technology at the 
    Massachusetts Institute of Technology, tells us there's a "shift" from an analog 
    world in which our identities are generated from within, to a digital world in 
    which our sense of self is intimately tied to our social media presence.

The way I understand this quote, it's opposed to centuries of sociology/psychology, cf. Aristotle's zoon politikon and Lev Vygotsky's “Through others, we become ourselves.”

My point is, the nature of the influence of others on ourselves has not changed, only the medium this influence goes through is different. And needless to say that this new medium is nothing more than a complement to all others through which we already achieve social presence.