[sneak]

I signed up for Google Plus reluctantly, mostly just to use hangouts as Skype doesn't work on the ARM Chromebook.

I don't use Facebook and I host my own email, mostly because I'd like to keep my social graph private.

However, Google knows everyone I'd have added on Plus already - and offers to add them for me. How? They've all uploaded their address books, and they all use gmail.

80-90%+ of my social graph is already known to them, just because my friends have already given them the data. My lack of participation in Google Plus is insufficient.

[canvia]

It is the same with smart phones. Even if you don't install any apps or link any of your profiles (fb, g+, etc) all it takes is for one person you know to upload their address book to "find their friends" and suddenly there is linked: your phone #, email, fb (your picture included), g+, all in one spot, all without your permission or knowledge.

Even if you try and secure your data and privacy, unless everyone you know does the same thing it is pointless.