* Speed. YDS is really fast.
    * Instant Feedback. YDS provides incremental search, much like you find in Firefox. As you type each character of your search, the results are updated instantly. Not only does this mean less typing, but you'll catch spelling mistakes a lot faster too.
    * Comprehensiveness. YDS indexes a lot of file types. Over 200.
    * Built in Preview: YDS renders a preview view for most of the 200+ file types and enables you to page through the preview, so you don't need to launch the full-blown application just to see if you've found the right document. You can page through a PowerPoint, Word or PDF doc, examine individual cells in Excel, or even play an mp3 file--right there in YDS.
    * Actions. If you right click on a result, YDS provides a context-specific menu that allows you to do things with the email or document: reply, forward, print, open, etc.
    * Cost. YDS is free.