Something that is going to be critical as we digitize our lives is this concept of variable privacy. What you share with who should not be a black and white issue, but one of subtle rings of trust. Your context will affect where people (and brands) sit within these rings of trust and entities may move in and out over time.
A company that is playing with this concept, ImInTa is discussed here http://www.webware.com/8301-1_109-9869813-2.html but there will be a lot more to come on this subject as people start to look for tools to manage who gets to know that they bought a book on Amazon or took a picture of their dog.
