Microsoft
http://sharepoint.microsoft.com/en-us/product/capabilities/search/Pages/Fast-Search.aspx

Microsoft FAST Search Server 2010 for SharePoint offers a new choice in enterprise search. Combining the power of FAST with the simplicity of SharePoint, FAST Search Server 2010 for SharePoint delivers an exceptional intranet and people search experience and a platform for building custom search-driven applications.

“With FAST 2010 and SharePoint, we’ll be able to give more specific results based on user context so our users are getting the information they need.”
Jeremiah Werner, General Mills

• Search in the language of your business: Use content processing to automatically create metadata.

• Tune relevance to meet diverse needs.

• Search content based on context.

• Make search more visual.

• Build search-driven applications.

Please see the 'Discovery - Who uses what systems' section for an updated list.

• FAST Guide: http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=8320

• FAST Video: http://sharepoint.microsoft.com/en-us/Pages/Videos.aspx?VideoID=17