There have been some amazing projects in recent years which have matured now to the point that a new alternative is possible. Wikia is funding and supporting the development of something radically new. Nutch and Lucene and some other projects now provide the background infrastructure that we need to generate a new kind of search engine, which relies on human intelligence to do what algorithms cannot. Just as Wikipedia revolutionized how we think about knowledge and the encyclopaedia, we have a chance now to revolutionize how we think about search.
Note: Contrary to misunderstandings in the press, Wikia is not a Wikimedia project.