Google recently announced an application to help users search US patents more easily. Read their Google blog entry here. This is the patent search site.
The first thought that came across my mind when I heard about this is (nasty mind?) - "Wow, it gives Google a wonderful insight into what people are possibly looking at - and - possibly try and patent (or bring out products, etc) some or a derivative of those (after due guessing on what can be a possible idea for such-and-such search terms) in case nothing is already available".
I may be way off base in such an assumption, but it's possible (at least theoretically).