AbdulAlhazred
Legend
An approach that's been said before (but I'll add my 2cp) is to "shift" the focus from "finding stuff out" to a more "what should we do with all this info"?
Since in Zeitgeist, the nature of who the "real" good guys are is a very up-in-the-air question, you can use throw all the available information you can think of at the players and still have meaningful discourse going on. The game can also promote some very involved role-play as the players have access to a lot of in-game information on which they can rely. If they are "note-takers" this can lead to incredible sessions of roleplay and "strategising".
2nd option:
Don't do this often (very, very rarely in fact) but you can also set up "wrong info" situations where the information they get leads them to make a very bad decision (and they will follow this correct information with great certainty, since they "know" they can't fail) - this can be very good for the game, but the timing and the frequency must be very precise.
But, and I can't stress this enough - don't do this often!
Right, one of the best ways is to face off the PCs against an evil mastermind, Moriarty to your Holmes. At first the players will not realized the existence of Moriarty and be easily mislead, but soon clues will begin to accumulate. Of course its a bit hard to do this with a pre-existing set adventure path, but there's always tweaking things a bit...
Actually this all sounds like a pretty fun kind of situation to have. breaks the mold of the usual dungeon crawling loot-mongers a bit.