During the last three months I studied logical programming, focusing on ProLog, and thought that it could be interesting to use its powerful deductive capabilities to improve web searches, making them more logical and natural.
I googled a bit and discovered that, as always, there's someone who's developing in that direction: Powerlabs is a San Francisco company, working on a search engine based on natural language processing; they're trying to push web searches further the "simple" matching of keywords.
Actually, I don't have any idea of the languages and algorythms they're using (I just read they're seeking RoR programmers for the front-end... GOOD!), but the idea is quite similar. Are they gonna be next Google?