So this is a big deal if you work on IT systems in Virginia:
http://www.npr.org/2...d-the-nsa-leaks
When dealing with catching criminals using tech, you have to act fast so that you don't miss out on important information.
For quickest turn around on getting permission to pull private data, I would imagine this IT system uses a web form in which you 'request' a wire tap by filling out lots of information fields.
These requests are probably pushed to a queue (maybe with REST, maybe SOAP) that a committee reviews. They maybe discuss it in person, maybe not, but eventually someone clicks 'Approve', 'Deny' or pushes it to some other 'Needs additional review' queue.
Once it's approved, the nerds, secret agents, and technology does the rest.
As for big data gathering, of course its happening and it will grow more. (Moores Law?) If it can be measured on the electromagnetic spectrum, rest assure it's frequency and amplitude can be recorded.