Before Facebook became so popular, people would never have thought it acceptable to post personal information on a public site and expect no consequences as a result. People share intimate details about private relationships as easily as guests on a Jerry Springer television show do. Nothing is considered truly private any more.
Facebook has definitely changed our notion of privacy.Instead of sharing our most intimate thoughts with just our closest friends the whole world now knows.While some might feel that this would make them famous others just want to keep their thoughts to themselves but know it might not be possible with Facebook around.
It has little effect on our privacy because it is us who choose what we share or post and reveal about ourselves. We can choose to hide what we want to be private. Facebook has no control over these matters. Privacy is something we, the users have to be careful about.