Microsoft announced today on the Windows Vista Blog the immediate preview release of Windows Search 4.0. This represents a new version of the search engine included with Vista RTM that until now had received no further improvements. The release is also extended to other operating systems that includes Windows XP, Windows Server and its 64-bit versions.

Numerous improvements are part of this preview release including: Performance enhancements of up to 33% compared to Vista RTM, Remote Index Discovery for PC-to-PC search on every supported version of Windows, Rollback Recovery where your search index will roll back to the last known good state, Support for the Encrypting File System (EFS), Reduced affect on Microsoft Exchange when you index e-mail in online mode, and there is no local cache,

In my personal experience, I have had little success using Vista's built-in search due to its lacking performance compared to, say OS X's Spotlight search, which made me shut down the search service permanently. Perhaps this is a good time to give it a try again, and see what direction Microsoft is really taking on enhancing Vista post-SP1.