How to build a natural language search engine. YahooAnswersAPI + AnswerBag API + index all FAQ webpages + index YELP and similar Q&A sites. That is it. Then when you get bought for that secret underlying technology send me a check. Matter fact don't. Send it to a educational charity in Africa or the 100 laptop project. Edit: I know this because I got one of my co-workers to do it for me in the past using only the Yahooanswers api and believe it anyone who tried it loved it although it was more fun than helpful.