When data breaches are intolerable, obscurity is not the way to secure the data; however, obscurity is a reasonable way to enhance your overall privacy. Facebook Graph has the potential to obliterate, or vastly reduce, obscurity. Loss of obscurity is really something we should be concerned about:
Obscurity is the idea that when information is hard to obtain or understand, it is, to some degree, safe. Safety, here, doesn't mean inaccessible. Competent and determined data hunters armed with the right tools can always find a way to get it. Less committed folks, however, experience great effort as a deterrent.
Accurately targeting the potential harms and interests at stake is only the first step in the debate about Graph and other similar technologies. Obscurity is a protective state that can further a number of goals, such as autonomy, self-fulfillment, socialization, and relative freedom from the abuse of power. A major task ahead is for society to determine how much obscurity citizens need to thrive.