Windows Desktop Search (WDS) is the search technology that lets users quickly find almost anything on their computers, including e-mail messages, calendar appointments, photos, documents, and more. In WDS 3.x, the search engine is now a system service but it retains the desktop performance features of previous versions of WDS. WDS 3.x has been optimized in its integration into Vista to give a superior experience compared to WDS on older machines. WDS uses simple search syntax to search for information that the user has selected to index. This means that when a user types "email from:john date:yesterday", WDS will list all e-mail messages that the user received yesterday from anyone named John. Users familiar with search syntax can use advanced keywords (Advanced Query Syntax) to specify everything from file types to date ranges as well as specifying which folders to search in. WDS returns results in a rich Windows Explorer environment, so users can quickly preview, filter, and act on search results
WDS 3.01 Admin Guide