These GCHQ minutes from December 2010 describes NSA advances in using voice analytics – including identifying individual cell towers in Afghanistan where Arabic was being spoken: see the Intercept article Finding Your Voice, 19 January 2018.
This undated GCHQ presentation describes some of the Question Focused Databases (QFDs) developed to analyse the massive amount of raw data the agency collects from undersea cables: see the Intercept article Profiled: From Radio to Porn, British Spies Track Web Users’ Online Identities, 25 September 2015.
This NSA presentation from 19 June 2009 explains the metadata capabilities of XKeyScore: see the Intercept article XKEYSCORE: NSA’s Google for the World’s Private Communications, 1 July 2015.
This undated GCHQ presentation proposes a deanonymisation attack against Tor users based on the collection of data from exit nodes owned by the agency: see the Der Spiegel story Prying Eyes: Inside the NSA’s War on Internet Security, 28 December 2014.
This 32-page NSA presentation dated 25 February 2008 details XKeyscore, a tool used to search unfiltered internet traffic in real time. Two slightly different versions of this presentation have been published; both follow below: see the Guardian article XKeyscore: NSA tool collects ‘nearly everything a user does on the internet’, 31 July 2013.