From Dan Geer's talk "Cybersecurity as Realpolitik" (which everyone should hear[1]/read[2]):
>> There are so many technologies now that power observation and identification of the individual at a distance. They may not yet be in your pocket or on your dashboard or embedded in all your smoke detectors, but that is only a matter of time. Your digital exhaust is unique hence it identifies. Pooling everyone's digital exhaust also characterizes how you differ from normal. Privacy used to be proportional to that which it is impossible to observe or that which can be observed but not identified. No more -- what is today observable and identifiable kills both privacy as impossible-to-observe and privacy as impossible-to-identify, so what might be an alternative? If you are an optimist or an apparatchik, then your answer will tend toward rules of data procedure administered by a government you trust or control. If you are a pessimist or a hacker/maker, then your answer will tend towards the operational, and your definition of a state of privacy will be my definition: the effective capacity to misrepresent yourself.
>> Misrepresentation is using disinformation to frustrate data fusion on the part of whomever it is that is watching you. Some of it can be low-tech, such as misrepresentation by paying your therapist in cash under an assumed name. Misrepresentation means arming yourself not at Walmart but in living rooms. Misrepresentation means swapping affinity cards at random with like-minded folks. Misrepresentation means keeping an inventory of misconfigured webservers to proxy through. Misrepresentation means putting a motor-generator between you and the Smart Grid. Misrepresentation means using Tor for no reason at all. Misrepresentation means hiding in plain sight when there is nowhere else to hide. Misrepresentation means having not one digital identity that you cherish, burnish, and protect, but having as many as you can. Your fused identity is not a question unless you work to make it be.