This NSA slide from a 2012 presentation on Cyber 702 Authorities shows that the agency’s authority to undertake warantless wiretapping of US persons’ internet traffic was extended over the course of 2012: see the New York Times article Hunting for Hackers, N.S.A. Secretly Expands Internet Spying at U.S. Border, 4 June 2015.
This undated NSA Menwith Hill presentation describes SPINALTAP, a project to combine data from active operations and passive signals intelligence: see the Der Spiegel article The Digital Arms Race: NSA Preps America for Future Battle, 17 January 2015.
This Boundless Informant slide shows the immense number of phone (DNR) and internet (DNI) metadata records collected day-by-day between 10 December 2012 and 8 January 2013 for NSA Special Source Operations from a number of sources including XKeyScore: see the book No Place To Hide, 13 May 2014.
This Special Source Operations presentation describes the NSA’s problems with overcollection of data from email address books and buddy lists: see the Washington Post article NSA collects millions of e-mail address books globally, 14 October 2013.