The Wayback Machine - https://web.archive.org/web/20140320040225/http://www.theguardian.com/world/interactive/2013/nov/01/prism-slides-nsa-document

NSA Prism program slides

Prism, according to the Snowden documents, is the biggest single contributor to the NSA's intelligence reports. As a 'downstream' program, it collects data from Google, Facebook, Apple and others
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