Byron Miller has posted an overview on Kuro5hin about the Mozdex search engine, a service that will provide open information about their page ranking strategy. The indexing process is performed by Nutch, while the search app runs on Tomcat and Lucene. He ends with this open question (for which there are many responses):

Do you think it is actually feasible to work on a process that stays ahead of the cheaters or do you believe it will be something doomed to fail just because its competing against the likes of Yahoo or Google? Source.