The main support for this claim are the leaked documents by Snowden that were pusblished in The Washington Post and The Guardian in 2013. You can find an archi

The main support for this claim are the leaked documents by Snowden that were pusblished in The Washington Post and The Guardian in 2013. You can find an archive of the article here: https://www.webcitation.org/mainframe.php https://www.webcitation.org/mainframe.php Thankfully, the NSA slides were directly included by wikipedia, so we don't have to hunt them down: https://en.wikipedia.org/wiki/PRISM_(surveillance_program)#/media/File:PRISM_Collection_Details.jpg https://en.wikipedia.org/wiki/PRISM_(surveillance_program)#/... We can see that PRISM targets (or should I say, partners) list contains at least: Microsoft, Yahoo!, Google, Facebook, YouTube, AOL, Skype Apple. As usual, this is what we know. Meaning what could be extracted, proven, communicated and accepted by the public. A pretty big filter already.