The search engine is a tricky system because it's very easy to mess it up with words that have become common over the last, nearly 2 million posts.
Needless to say, including words like "the", "of" "Neo" "geo" or a lot of other words will wreck a search by bringing up too many hits. Alas, making the search engine able to handle all of that would screw up the entire operation of the website.
It's an imperfect system, but difficult to correct in an acceptable manner.