Google Search Appliance, a box that indexes documents from a company's intranet and web sites, was updated and the list of the new features includes:
* search clustering (automated grouping of search results by topic)
* mark authoritative sources (similar to the way Custom Search Engines work)
* sitemap generator for company's sites, that can be submitted to Google Webmaster Tools.
* integration with Microsoft SharePoint 2003 and 2007 (the appliance can index SharePoint documents)
While the new version adds features already available for consumers (sitemaps, search bias), it will be interesting to see if Google decides to add clustering to the web search. Other search engines that have this features (like Clusty) don't have extraordinary results, but may help you view the big picture and guide you in refining your query.