UPDATE: Apple, Facebook and Google have all denied involvement in the PRISM program.
EARLIER: A top-secret April PowerPoint slideshow details how the National Security Agency partnered with nine tech companies, including Apple, Microsoft and Google, to monitor users' activity.
The NSA got direct access to these companies' servers in order to directly watch user communications, according to the presentation obtained by the Washington Post and the Guardian.
The program, called PRISM, is nominally aimed at foreign actors, but as the Post reports, purely domestic communications could easily end up in NSA hands, so long as an algorithm estimated at least a 51 percent probability that they were foreign.
Here are the slides showing how the NSA got its hands on your data:
Nine companies participate in the program, starting with Microsoft in 2007. The following entrants were Yahoo, Google, Facebook, PalTalk, YouTube, Skype, AOL and Apple. YouTube is a Google subsidiary and Skype is a Microsoft subsidiary.
The NSA gets vast amounts of information from the participating companies — email, chats, videos, photos, stored data, voice-over-IP communications, and more. The companies also take "special requests."
Many foreign communications travel through the U.S., giving the NSA the opportunity to intercept them.
SEE ALSO: The Guardian's report on how the NSA mines Internet user data