= a free distributed search engine, built on principles of peer-to-peer (P2P) networks
URL = http://yacy.net/
Originally from Wikipedia, updated and expanded in January 2011.
"YaCy (read "ya see") is a free distributed search engine, built on principles of peer-to-peer (P2P) networks. Its core is a computer program written in Java distributed on several hundred computers, so-called YaCy-peers. There are currently (2010) 600 peers active each month and the cumulative index has grown to 1.4 billion documents. Every YaCy-peer independently crawls the Internet, analyzes and indexes found web pages, and stores indexing results in a common database (the index) which is shared with other YaCy-peers using principles of P2P networks. There are versions of YaCy for Windows, Linux and MacOS.
Compared to semi-distributed search engines, the YaCy-network has a fully decentralised architecture. All YaCy-peers are equal and no central server exists. It can be run either in a crawling mode or as a local proxy server, indexing web pages visited by the person running YaCy on his or her computer. (Several mechanisms are provided to protect the user's privacy.)
Access to the search functions is made by a locally running web server which provides a search box to enter search terms, and returns search results in a similar format to other popular search engines.
YaCy also provides code snippets to support the integration of YaCy search into web pages. There is a search widget and demonstration snippets are provided by the YaCy administration interface. The code to integrate YaCy as a web page search engine of choice can simply be copied and pasted into the page.
As any peer-to-peer application, YaCy search will only grow and eventually be able to compete with commercial search, if enough people (yes, that includes YOU) actually download and run the application.
The program is released under the GPL license." (https://secure.wikimedia.org/wikipedia/en/wiki/YaCy)
- Faroo (Faroo is implementing a commercial, advertising based model of distributed search. An important limitation is that their search engine is only available for Windows.)