To Drill Down...

But training materials for XKeyscore detail how analysts can use it and other systems to mine enormous agency databases by filling in a simple on-screen form giving only a broad justification for the search. The request is not reviewed by a court or any NSA personnel before it is processed.

XKeyscore, the documents boast, is the NSA's "widest reaching" system developing intelligence from computer networks – what the agency calls Digital Network Intelligence (DNI). One presentation claims the program covers "nearly everything a typical user does on the internet", including the content of emails, websites visited and searches, as well as their metadata.

To drill down means to move from summary information to detailed data by focusing in on something. In a GUI-environment, "drilling-down" may involve clicking on some representation in order to reveal more detail.[1]

To drill down through a series of folders, for example, on a desktop means to move through the hierarchy of folders (from the top downwards) to find a specific file or to click through drop-down menus in a GUI. Clicking on an item moves you to a level of greater detail. When an online user accesses more and more pages of the website, he or she may delve deeper into the content of the site. 

Any questions?

Addendum: The NY Times just posted a piece describing the extent of the NSA's push to eavesdrop the world. Needless to say, quite ambitious and eminently doable give just how powerful and persuasive systems and the net have become in the 21st century.

The Obama administration on Wednesday released formerly classified documents outlining a once-secret program of the National Security Agency that is collecting records of all domestic phone calls in the United States, as a newly leaked N.S.A. document surfaced showing how the agency spies on Web browsing and other Internet activity abroad.

Together, the new round of disclosures shed even more light on the scope of the United States government’s secret surveillance programs, which have been dragged into public view and debate by leaks from the former N.S.A. contractor Edward J. Snowden.

Seems the eminent Mr. Snowden has been right all along regarding the emergent surveillance state, courtesy the NSA. As a bonus, click here to download the complete XKS manual. Who knows, we, the great unwashed, could use something as user friendly and as powerful as this to sift through the never ending cascade of emails that inundate us 24/7. :)