I have recently given an interview to Aaron Wall of SEO Book where I said that
“the best way of taking a marketshare from Google is not by building a better search destination site, but by changing the paradigm – give reasons for users not to make a decision to go to a search engine. Because when they think search engine, they think Google.
Essentially, what Quintura Site Search does is creating environments where users keep exploring the passions, their interests, their information needs from where they are on the Web. People go to search engines when they can’t find what they want where they are.”
Answering the question on how to rival Google, it’s not about money, it’s about changing the paradigm.
Please, read the Quintura interview on SEO Book