But he's not even denying that they directly collect information from those companies. It could be that the slideshow is misleading and PRISM is not the collection program but just the interface to the databanks from the collection program.

But we aren't upset about what PRISM is doing we are upset about what the NSA is doing. So clearing PRISM's name is pointless and could just be a way to mislead without directly lying. Or he may just be lying.

I don't think that Glenn Greenwald would stake his reputation on just a PowerPoint. He claims on Twitter that he has "highly detailed technical NSA materials on how they eavesdrop". [1] Though I'm not sure if that is a reference to the telecom spying or Internet spying.

[1] https://twitter.com/ggreenwald/status/343470800784982016