I can personally confirm Palantir Prism is not NSA's Prism. I helped build that team and write that software in 2006. It was Palantir Finance, and it was built for use at hedge funds and financial houses as a quant analysis platform for traders.
Edit: It might not be obvious to some, but code names are always in all caps.
Nope https://en.wikipedia.org/wiki/Code_name#Famous_code_names
From http://www.designation-systems.net/usmilav/codenames.html#_C...
"Code Words are printed using all capital letters."
Palantir denies it, and then one of the developers on the original project, a YC partner, comments on HN that the Palantir project had nothing to do with surveillance. Your response then demands that he prove a negative.
The question is: do they use a compiler written for the NSA by Ken Thompson?