Feature: Quick Look
How it works: Quick Look has the potential to change the way Mac users interact with their computers. It brings super-quick access to your files by allowing you to preview a variety of files without opening them in their associated applications. Instead of opening a file by double-clicking on it in the Finder, if you hit the spacebar you'll see a live preview pop up. Also with Quick Look, the various supported document icons become live preview thumbnails. Supported file types include "images, text files, PDF documents, movies, Keynote presentations, Mail attachments, and Microsoft Word and Excel files." Third
Who will use it: Everyone. Like Cover Flow, Quick Look has the potential to really speed up the process of finding a particular document since you can scan contents without opening them.