MozDex
mozDex was a project to build a internet scale search engine with FOSS technologies like Nutch. Since its search algorithms and code was open it was hoped that no search results could be manipulated by either mozDex as a company or anyone else. As such, instead of having to trust mozDex to be fair, it puts the trust on the community of users through the same "peer review" process that is believed to enhance security of Free Software like Linux.
Read more about Mozdex.