This page from GCHQ’s internal GCWiki, last updated on 1 May 2012 documents progress in a variety of the agency’ projects: see Facing Data Deluge, Secret U.K. Spying Report Warned of Intelligence Failure, 7 June 2016.
This undated page from GCHQ’s internal GCWiki provides a definition of “event”, the term the agency uses to refer to a metadata record, showing the variety of data collected: 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 NSA presentation from May 2010 describes the kinds of information the agency can extract from smartphone traffic, describing the use of mobile apps as a “golden nugget”. Note that this is the first version of this document released online: see the Pro Publica article Spy Agencies Probe Angry Birds and Other Apps for Personal Data, 27 January 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.