What's too much data when it comes to privacy?

I stumbled on an article in NYTimes describing National Security Agency's program for collecting and graphing social connections between people based on information collected online, which supplements phone calls and etc. Since we mentioned the older generation with location services on iphones in an earlier class, the topic resonated with me to investigate further. It seems that there is a VERY thin line between preventing horrible incidents and interfering too much with people's lives (big brother style). While i understand the necessity to collect and analyze online interactions and movements, I believe people should have visibility into how their data is used. Specifically, the NSA does not reveal statistics on success of the program, as well as not mentioning failures of accusing people based on misconstrued data. The government needs to regulate these program more and introduce some transparency (without undermining effectiveness of the program, if there is any) as online interactions are becoming more and more prominent and integrated in every day life.

Here's the entire article describing the program
http://www.nytimes.com/2013/09/29/us/nsa-examines-social-networks-of-us-citizens.html?pagewanted=all&_r=0

Liza Shepeleva