Skype, WhatsApp, and Yelp have accessed my contacts list data thousands and times, and none of the companies are sure why.

The companies -- Microsoft, which owns Skype; and Facebook, which owns WhatsApp; and Yelp -- were all unable to explain why their apps had accessed the contacts list in my Android phone so often. BlackBerry's Priv, the smartphone maker's debut Android phone running "Lollipop" 5.1.1, comes with an app, dubbed DTEK, which monitors and notifies users when data has been accessed, when, and for how long, including a user's location, contacts, text messages, camera, and microphone.

Since the first of many leaked documents showed that the NSA has been gathering phone records as part of its anti-terrorism program, there's been an ongoing fight over just what these records reveal.

To supporters, the metadata collection is a limited system that's rarely queried and doesn't contain enough information to be considered an invasive search: the NSA has said it doesn't collect either the content of calls or the names attached to phone numbers.

As many technology and legal experts on the other side say, though, metadata matters, and a Stanford Security Lab project demonstrates that removing names from a database doesn't effectively mean much.