Luckily for Palantir whether or not it works is classified. I have my doubts. I'm sure it "works", but I'm also sure it's a giant waste of money and Americans are not safer because we're funneling millions of dollars to Palantir.
I messed around with the demo they used to have on their website. It seems to be very much an answer to the 9-11 failure to connect the dots problem.
Unify search, build semantic links.
It was a very manually intensive tool based on what I saw. Very little automation, more like those pictures and strings you see in crime shows on TV...but on a computer.