I never liked Spotlight, the Mac search tool. I use it basically just to launch Applications when Quicksilver is not available.
I always suspected it was not being accurate...or at least not relevant. And I've tweaked it and set up Do-Not-Search folders and so on and so on..but in terms of the concept of a Sematic Desktop, Spotlight just doesn't seem to be quite working for me.
Today it really didn't work for me. Notice the discrepancy in the screenshots.