One of the most popular requests I see from customers regarding enterprise search is to be able to refine search results by category with a simple click.

The best free way to enhance MOSS 2007 search with this type of feature is via the free faceted search web parts out on codeplex: http://www.codeplex.com/FacetedSearch

Want to check it out?  Here's a live demo: http://www.wssdemo.com/Search/Pages/results.aspx?k=search. Check out the "Search Facets" section on the right.

The new 2.0 release encapsulates foundation changes in the design and code, that provides perfect balance between accuracy and performance.

Highlights:

• Multi-thread processing. 1st thread runs for up to 500 facets synchronously, while the 2nd thread is running asynchronously against up to ~30,000 facets
• Client side refresh (not AJAX) that updates only Facets web part w/o page refresh
• Web part connections to pass Facet settings to the Bread Crumbs
• Extended facet schema now supports:
• Facet icons. Default icon per Facet name complimented by an icon per Facet value
• Friendly names for facet values
• Exclusions. Allow exclude facet when values match pattern
• Built-in wild-card match, especially useful for exclusions
• Improved search syntax, added supports for sentences and quoted phrases

This release includes numerous fixes and complemented by extended documentation.