It seems that I know too little for the world of the search engines. I will try to summarize the search engines that can be used for real applications. The first one that I know was Lucene. There is a lot of code build on top Lucene

.

• SOLR
• Compass
• sphinx
  • ruby interface for it http://blog.evanweaver.com/files/doc/fauna/ultrasphinx/files/README.html

Then it seems that those seach engines are nice connected to data grids, like Terracotta. On this page there is also nice tutorial how to start with the grids. Search engine resources stopwords:

• http://en.wikipedia.org/wiki/Stop_words
• http://www.semantikoz.com/2008/04/02/free-stop-word-lists-in-23-languages/
• http://snowball.tartarus.org/algorithms/swedish/stop.txt
• check my list of stop words

CouchDB

• http://couchdb.apache.org/docs/overview.html
• http://thailehuy.wordpress.com/2009/02/13/couchfoo-like-activerecord-but-for-couchdb/