Spotlight also lives in your Finder windows (right where the old Search field was in previous versions of Mac OS X), but when you search here, you get a little bonus — savable searches.
So, for example, you search for all the email, images, and other junk sent to you by your friend Alan. When you do this in a Finder window, the Finder window updates to show the results right there in your window. Oh, but there’s more. Now you’ll find a Save button near the top-right side of your window. If you click it, it saves your results in a folder in your sidebar, where you can re-access those files at any time. How cool is that! But this is no ordinary folder, my friend. This is a Smart Folder, which means the next time Alan sends you something (or you mention Alan in a document, email, etc.), it will automatically be added to that Smart Folder. It’s live, baby!