We have been using Lucene for a while. It is embedded in our InfoMinder product (mostly for filtering content). I was happy to find an entire Enterprise Search solution called Solr. It is an Apache project (in incubation) and seems to have some great features.

Solr is a standalone enterprise search server with a web-services like API. You put documents in it (called “indexing”) via XML over HTTP. You query it via HTTP GET and receive XML results.

• Advanced Full-Text Search Capabilities
• Optimized for High Volume Web Traffic
• Standards Based Open Interfaces - XML and HTTP
• Comprehensive HTML Administration Interfaces
• Scalability - Efficient Replication to other Solr Search Servers
• Flexible and Adaptable with XML configuration
• Extensible Plugin Architecture

There seems to be even hosted solutions for Solr. What can you do with it?

By buying a box and hosting Solr on it, you may have a simple Search Appliance. This can be used by enterprises for document search in the intranet. It can also be used as the backend of a content management system or a wiki. It will be interesting to play with this tool. It is also a potential backend for lots of Search mashups.