Facebook is currently the world's most popular social­networking site

Facebook is currently the world's most popular social­networking site. Many members have revolted against Facebook for constantly changing its user information policy. What is the current user information policy and what are the legal complications associated with it?
What are the implications of Facebook changing its user information policy?
Is Facebook legally required to notify users of changes in their privacy policy, if yes, in what manner?
Facebook Grapples With Privacy Issues or another source