Social norms about privacy are obviously changing. No one knows yet where they will end up, but clearly we are undergoing a generational transformation.Rebooting Library Privacy in the Age of the Network (via JoHo)
Norms are what holds if exceptional circumstances need to be cited to justify contrary actions. In a grocery, the norm is that once an item has been placed in a shopper's cart, other shoppers are not free to take it for themselves; if you do wish to take an item from another shopper's cart, you need to give a reason.
In software and social systems, norms are expressed as defaults: functionality and configurations that encourage certain uses and behaviors. Defaults and norms are fundamental to human society; without them, we would have to go back to first principles every time we entered a grocery, and would have to renegotiate fundamental rules of behavior every time we queued. They are the implicit that enables us to live together.
Privacy is a set of norms expressed by defaults. In a library, for example, the norm is that you can glance at what someone is reading, but if you stare over someone's shoulder, it will eventually become rude, and after some more staring, a librarian will be called over.
As these norms go through a generational change, it is crucial that libraries get the defaults right -- or at least righter. There is, however, no possibility of perfection: The privacy norms are changing, the norms are less homogeneous than ever before, and the changes to the defaults will themselves influence the norms.
Despite this uncertainty, libraries need to do their best to re-balance the values and risks of publicness, in order to address the new norms, and new opportunities