More detail here than I've seen elsewhere. In particular, this explanation of what PRISM actually does- "PRISM works well because it is able to handle several

More detail here than I've seen elsewhere. In particular, this explanation of what PRISM actually does- "PRISM works well because it is able to handle several different types of data streams using different basic encryption methods, the person said. It is a "front end" system, or software, that allows an NSA analyst to search through the data and pull out items of significance, which are then stored in any number of databases. PRISM works with another NSA program to encrypt and remove from the analysts' screen data that a computer or the analyst deems to be from a U.S. person who is not the subject of the investigation, the person said." It mostly sounds like a typical DB query front end, which accesses DBs built up from individual record requests from the tech companies. But then there's the part about handling different kinds of encryption on the input side, which is puzzling.