One has to define privacy in the digital environment - and it isn't anonymity, in fact privacy was never based on nor provided by anonymity.
Privacy is the right to 'not be interfered with' - such that any information about you that has no relevance to incurring a social harm can't be used against you. Anonymity is great for 'evil doers'. Child abusers, money launderers, serial killers all love anonymity, because it hides information that is relevant to social harm.
In the digital environment privacy has to do with letting people have choice about how their information is used of personal conveniences and social good. As Kevin Kelly has noted "how much does the system have to know about you to really serve you well?" For example I wouldn't have to carry money, ID, credit cards if the system knew where I was all the time and I updated it regarding all my means of financial/commercial exchange. This could be hugely convenient to me. And with location data along with dna data identity theft would be a thing of the past. A person can only be in one place at a time and with dna - I would be the only me possible.
A corollary is how much does the system have to know about you to really serve the social good'. For example, all of our dna data is there in the cloud available, along with data about how we exercise, what we eat, where we've been. Any anomalies in my dna could actually become sources of income because they offer unique research opportunities. This sort of data and analysis would be a huge benefit to us all.
Where privacy comes into play is the necessary transparency so that I knew how my data was used and that I could have a choice in obtaining and/or sharing the benefits, With requisite alerts, I could be notified when ever anyone 'looked at or used' my data to ensure I approved, understood and mitigate the way it was being used.
Privacy is a nuanced balance between personal and social ownership of our information to ensure personal and/or social benefit.
What facebook is all about is using our data for profit without consideration of personal or social benefit to us. I wants to keep the data we generate in its walled garden so it can charge us and any other '3rd party' rent this data. It wants to fence a knowledge/data commons that is of great benefit personally and socially in order to 'appropriate' this commons in order to make money through rent-seeking.