There is a new video up on the Youtube channel. It is all about tagging files and how to find these tags within Spotlight. If you have many files all along the same theme spread over your Mac, you can tag them with the same comment. This means when you want to find them again, as long as they have this comment, they will turn up. It is very quick and very useful. I like to use if if I have a set of files over many disks and folders. Its a quick way of locating them again.