Privacy in the 21st Century

How do we best define "privacy" in the 21st century? Certainly, "anonymity" would not be the likely answer, especially for today's society in the United States. Anonymity has been difficult to achieve for some time in our country, at least dating back to the issuance of Social Security numbers. So what is an appropriate definition for today's paradigm? One can posit that privacy today is the binding of a true and accurate identity to its claimant, such that the identity cannot be stolen, reproduced, or altered in any way. Perhaps most importantly to those who hold their privacy rights as sacred, the lack of ubiquity of reference data across domains might very well be defined as the underpinning of 21st century privacy. What is meant by this? If an individual provides a rendering of his or her identity in digital form (i.e. biometrics), let's say to a retailer, he or she would have the presumption in a society such as ours that the digital identity would not be shared, or inadvertently released, to another and separate database that might make disadvantageous use of that identity (such as a criminal database). In other words, containment of digital identities within a single domain ensures that individuals' identities do not become overly accessible to parties who have an alternative intent for using those identities. Furthermore, digital identity renderings that are in uncommon formats or modalities reduce the likelihood that an errant release of the digital identity can lead to any significant harm. An example of this would be the disparate effect of a person's fingerprints being accidentally lost or shared, versus a template of the vein pattern in his hand or finger.