I've lost count of the number of times I've either asked a question or been answering a question only to have it closed as an exact duplicate. But searching for the question turns up a list of seemly unrelated results using the sites builtin search. Then if I switch to a general web search engine and limit its scope to just SO, SF or SU I find the question within the first two or three results.
Why is this?
I'm pretty sure this isn't an exact duplicate of another question though I did find some that were at least somewhat related (using google).
I also have gotten (somewhat) better results by simply typing a question and browsing the generated list of related questions. Still a search feature that doesn't return good results isn't going to be used by most people.
Common sense would suggest (though common sense isn't always the best indicator) that a targeted solution to a specific problem domain should be superior to a generalized solution. In most cases this appears to hold true.