The perfect search engine be a small microchip implanted in our brain. It would act as an instantaneous connection between the vast complexity of our brain and the vast complexity of the Web. To find something, we would just have to think about it and the chip would match that concept with the most relevant destination online.
Unfortunately, such a development hasn't rolled out of the Google Labs yet. So for now, we have to shoehorn our thoughts into a small quarter-inch by three-inch box on the search engine's home page. We have to distill our thoughts into a few choice words and hope this provides the search engine with enough to go by. And there lies the ultimate vulnerability point of search. Often, our ideas are too big to capture in one or two words.