Hi,

You may want to check the tag http://del.icio.us/mbauwens/P2P-Search, where I monitor search-related developments.

Here is what I have in the section http://p2pfoundation.net/Category:Technology:

# For the most fully distributed Peer to Peer Computer Networks at present, please check out Tribler ;Peerple ; Wipeer
# Research into more fully distributed P2P systems for the future: Chord, CX Project, Farsite, Globe Project, Oceanstore, Pastry

There is an important open search initiative based in Amsterdam as well. (should be able to find it through google or in the bookmarking tag above, I also wrote about it in the blog)

Finally, there are people in our network knowledgeable on this: Olivier Auber, Gwendal Simon, "Olivier Auber" "Anh-Tuan GAI" . I'll invite them, but otherwise, send me an email and I'll forward your query.

Yahoo is now using the Free Hadoop.Apache.org which is 'distributed' in that it is designed to run on thousands of machines, though usually in the same building...

http://developer.yahoo.net/blog/archives/2008/02/hadoop_production_...

Some big news in the world of Hadoop comes out of Yahoo! today. We believe we're now running the world's largest Hadoop application, a 10,000 core Linux cluster producing data used by the Yahoo! Search Webmap.

There is a p2p web indexer and distributed search index at

Yacy - http://www.yacy.net/en/

YaCy is a free search engine that anyone can use to build a search portal for their intranet or to help search the public internet. When contributing to the world-wide peer network, the scale of YaCy is limited only by the number of users in the world and can index billions of web pages. It is fully decentralized, all users of the search engine network are equal, the network does not store user search requests and it is not possible for anyone to censor the content of the shared index. We want to achieve freedom of information through a free, distributed web search which is powered by the world's users.