All re-ranking you can do is very limited with these services because they are black boxes: you don't see what factors went into ranking a page the way it happened, you can't tweak the weight of different factors, you can't add new factors. All you can have is hardcoded rules like "if there is a wikipedia page in the first 20 results, bring it on top" that don't really add much value, because if that wikipedia page is any good it would be on top already. With spam results it's similar: you can provide impressive customer service blacklisting spam on user requests, but major search engines are already pretty good in low-ranking spam so much that you don't see it if there are any other meaningful results.

Your marketing here on HN has been brilliant, you have some very interesting UI decisions and possibilities that Google doesn't have, but your added value is definitely not in improved ranking of results.