The only attempt I know about to build a one-answer-search engine is Goggle's 'I'm feeling lucky'. It is supposed to give users "the most relevant result that is not a paid advertisement" but when I tried to get the best result for the search words I'm feeling lucky" I got a narrow explanation which is certainly not the best since I found a better one.
I already wrote about the need to build a one-answer-search-engine. It seems that Goggle's 'I'm feeling lucky' is not it since it is not used enough and since it is not good enough.
What bothers me is that I don't see people who are looking for a solution to this problem of too many irrelevant results. It is like bad weather- many people complain about it but do nothing. I feel that if the question will be asked clearly search engine experts will find the way to give us a one-answer-search engine. It is not only a need it is also a challenge!