Search is predicated on the existence of the thing you're seeking. When you are searching the entire Internet that assumption is usually true -- i.e., something probably exists that answers most any question you can pose. Dave cited a person who diagnosed his dog with lyme disease and thanked Google for it. That person can thank Google -- but, he should probably have greater thanks for the person who wrote the article that helped them do it. This existence assumption just isn't true inside the enterprise.
I had not previously considered this.