Privacy: the quality or state of being apart from company or observation. What is private information, to me, is those things which I know about myself and no one else does. Once I share that information, or I act publicly to allow it to be deduced from my actions, it's no longer private. I can expect different degrees of privacy, depending on how I view the other people who share my data, but once the information is in someone else's hands, I really don't know just how valid any of those expectations are.
Privacy is not data security - that assumes that you understand the data isn't private and that you're arguing about subsequent control over redistribution of the data. Nor is transparency related to either one, because transparency implies you've given up on both privacy and control, and you want to be able to see how your information is being distributed.
It seems to me that these three totally different definitions are being used almost interchangeably in the arguments that are currently going on. Which means that someone arguing from a privacy standpoint is being rebutted by an argument about data security, which is being called a lie by someone who is arguing about transparency.
Anyway, this is one possible separation of terms that might promote better discussion in the NSA/data area. I'm sure there are others that might work, but this is what I've got at this point. Additional suggestions that could separate out some of the mess?