I'm wondering if the name of the project is a clue. Maybe they don't need access to the structured data. Maybe they just split the fiber optical stream using a

I'm wondering if the name of the project is a clue. Maybe they don't need access to the structured data. Maybe they just split the fiber optical stream using a 'prism' and pipe the output to Fort Meade. In which case, Facebook are not lying when they say that the NSA don't have access to their servers, but they do have access to their network traffic.