Facebook wants to give users control over who sees their information. From this morning's Globe: Facebook's allure is its privacy:

Chris Kelly, Facebook's chief privacy officer, said users want greater control over who sees their personal information, rather than expecting total privacy, or anonymity, the concept underlying much of the legal thinking on privacy for more than a century.

I would agree with this assessment. As I've noted before, think that Facebook's future success is dependent on its ability to provide users with fine-grained control over who can see their information, including information that they want to make available to people outside the Facebook universe.