I am going to guess that PRISM is a system which receives and parses the data files from those companies that are produced as a result of warrants/subpoenas/nat

I am going to guess that PRISM is a system which receives and parses the data files from those companies that are produced as a result of warrants/subpoenas/national security letters. So the excerpt from the NSA document that the Washington Post gave—"Collection directly from the servers of these U.S. Service Providers: Microsoft, Yahoo, Google, Facebook, PalTalk, AOL, Skype, YouTube, Apple" — may refer only to some kind of secure file transfer (private circuit with NSA hardware encryption, maybe). It's just a guess, but it could fit with the relatively low cost figure given ($20 Million).