Here's the description in the WaPo:
The National Security Agency and the FBI are tapping directly into the central servers of nine leading U.S. Internet companies, extracting audio and video chats, photographs, e-mails, documents, and connection logs that enable analysts to track foreign targets, according to a top-secret document obtained by The Washington Post.
The program, code-named PRISM, has not been made public until now. It may be the first of its kind. The NSA prides itself on stealing secrets and breaking codes, and it is accustomed to corporate partnerships that help it divert data traffic or sidestep barriers. But there has never been a Google or Facebook before, and it is unlikely that there are richer troves of valuable intelligence than the ones in Silicon Valley.
Equally unusual is the way the NSA extracts what it wants, according to the document: “Collection directly from the servers of these U.S. Service Providers: Microsoft, Yahoo, Google, Facebook, PalTalk, AOL, Skype, YouTube, Apple.”
Here are the previously top secret files which describe PRISM.
And a description of Boundless Informant.
The NYT provides background on the program - which can be traced back to 9/11 and has its defenders in Congress.
http://www.nytimes.com/2013/06/07/us/nsa-verizon-calls.html?smid=pl-share
